XPS L502X integrated webcam won't start, error message "Close the other video streaming applications to start video"

Question

Hello, i've been working with this issue for more than a week now. Have tried all the solutions on the net without any success.
Windows 7 home premium x64 is installed on the machine.
When trying to use any application using camera shows up a message, that webcam is used by another application. This pops up on Skype and Dell Webcamcentral. Ms Silverlight shows black screen, no message. The device is present under imaging devices in device manager. The driver installed is Microsoft 6/21/2006 ver. 6.1.7601.18208, status "device is working properly". Driver files: ksthunk.sys, usbvideo.sys and ctclsflt.sys after installing webcam central.
Here is what i tried:
1. Installing drivers from Dell.com in the correct order
2. Uninstalling webcam driver and letting windows install the driver from windows update.
3. Uninstalling windows driver and installing Quanta webcam driver before restart. Note, that in all 3 steps quanta driver never showed up in driver details in device manager.
4. Uninstalled skype.
4.Uninstalled all "usb root" in device manager, restarted, windows installed it's drivers, installed Dell_SX2210-Monitor_Webcam SW RC1.1_ R230103.
5. Uninstalled Webcamcentral, downloaded and installed ver 6.1 Skype.
6. Started windows in a clean boot state.
7. Installed process observer. Webcam is used only by skype, but skype gives "camera used by another app" error message.
8. Turned off laptop, removed ac power and battery, pressed power on button for 30 secs.
9. Tried to update driver through device manager - driver is up to date.
10. Reinstalled windows and installed chipset drivers + wireless drivers and let the windows update. Then installed all Dells drivers in the correct order.
11. Restored to the point before windows update and installed Dell drivers in the correct order.
12. Restored to the point after windows update again. Installed ms Silverlight, camera shows black screen. Room is light, tried a sheet of white paper close to the camera.
13. Tried different skype versions again, uninstalled skype.
14. Process observer shows that nothing uses webcam. Supportassist shows failure in webcam at all checkup stages. Supportassist suggests to turn of programs that might be using camera.
15. Tried all the steps before windows reinstall.
16. I gave up and ask for your help.
Here is Supportassist diagnostics log:
SupportAssist Log File
Sunday, April 12, 2015 6:42:12 PM
Overall Test Result: Failed
WEBCAM
Driver Provider:
Microsoft
Driver Version:
6.1.7601.18208, 6/21/2006
Capture To Screen Test
Test Started
4/12/2015 6:26:18 PM
Error Message:
Error creating the filter graph for rendering video.
4/12/2015 6:30:55 PM
Test Finished:
Failed (Error code: WWC02-7TM)
4/12/2015 6:30:55 PM
Capture To File Test
Test Started
4/12/2015 6:30:55 PM
Error Message:
Error creating the filter graph for rendering video.
4/12/2015 6:36:27 PM
Test Finished:
Failed (Error code: WWC01-XEI)
4/12/2015 6:36:27 PM
Edge Detection Test
Test Started
4/12/2015 6:36:28 PM
Error Message:
Unable to capture video frames.
4/12/2015 6:36:58 PM
Test Finished:
Failed (Error code: WWC09-VFH)
4/12/2015 6:36:58 PM
Luminance Depth Test
Test Started
4/12/2015 6:36:58 PM
Error Message:
Unable to capture video frames.
4/12/2015 6:37:28 PM
Test Finished:
Failed (Error code: WWC08-5TS)
4/12/2015 6:37:28 PM
RGB Channel Test
Test Started
4/12/2015 6:37:28 PM
Error Message:
Unable to capture video frames.
4/12/2015 6:37:59 PM
Test Finished:
Failed (Error code: WWC05-OKO)
4/12/2015 6:37:59 PM
RGB Color Depth Test
Test Started
4/12/2015 6:37:59 PM
Error Message:
Unable to capture video frames.
4/12/2015 6:38:29 PM
Test Finished:
Failed (Error code: WWC07-WLL)
4/12/2015 6:38:29 PM
RGB Line Amplifier Test
Test Started
4/12/2015 6:38:29 PM
Error Message:
Unable to capture video frames.
4/12/2015 6:39:00 PM
Test Finished:
Failed (Error code: WWC06-IV1)
4/12/2015 6:39:00 PM
RGB Line Driver Test
Test Started
4/12/2015 6:39:00 PM
Error Message:
Unable to capture video frames.
4/12/2015 6:39:30 PM
Test Finished:
Failed (Error code: WWC04-YMZ)
4/12/2015 6:39:30 PM
RGB Pixel Test
Test Started
4/12/2015 6:39:30 PM
Error Message:
Unable to capture video frames.
4/12/2015 6:40:00 PM
Test Finished:
Failed (Error code: WWC03-1VT)
4/12/2015 6:40:01 PM
System Summary
Product
Dell System XPS L502X
Service Tag
JQNQCT1
Express Service Code
429-708-457-81
Operating System
Operating System
Name
Microsoft Windows 7 Home Premium Edition (64-bit)
Service Pack
Service Pack 1
Build Number
7601
DirectX Version
11
Windows Directory
c:\windows
System Directory
c:\windows\system32
Maximum OS Memory
16.00 GB
System Name
INDRE-PC
User Name
Indre
Windows Experience Index
Base Score
5.9
Processor Subscore
7.5
Memory (RAM) Subscore
7.6
Graphics (Aero) Subscore
6.2
Gaming Graphics Subscore
6.2
Primary Disk Subscore
5.9
Assessment State
Valid Scores
Assessment Date
4/9/2015 7:23:35 AM
Windows Update
Automatic Updates
Automatic download and install
Last checked
2015-04-11 22:25:37
Security
Windows Update
Automatic Updates
Automatic download and install
Last checked
2015-04-11 22:25:37
Firewall - Windows Firewall
Windows Firewall Enabled
Yes
Motherboard
Manufacturer
Dell Inc.
Product
0NJT03
Chipset
Intel PCH HM67
ePPID
CN0NJT034864324S0399
BIOS
Vendor
Dell Inc.
Release Date
09/07/2012
BIOS Version String
A12
ROM Size
2.50 MB
SMBIOS
Version
2.6
ACPI Thermal Zones
TZ00
Current Temperature
65 C
TZ01
Current Temperature
65 C
Intel(R) Mobile Express Chipset SATA AHCI Controller
Interface
PCI
Location
PCI bus 0, device 31, function 2
Type
SATA Controller
Class
01h:06h:01h
PCI Identification
Vendor Name
Intel Corporation
Vendor ID
8086h
Device ID
1C03h
Revision
05h
Driver Provider
Intel
Driver Version
10.1.2.1004, 1-12-2011
Driver
c:\windows\system32\drivers\iastor.sys
Intel(R) 6 Series/C200 Series Chipset Family USB Enhanced Host Controller - 1C2D
Interface
PCI
Location
PCI bus 0, device 26, function 0
Type
USB EHCI Controller (USB 2.0)
Class
0Ch:03h:20h
PCI Identification
Vendor Name
Intel Corporation
Vendor ID
8086h
Device ID
1C2Dh
Revision
05h
Driver Provider
Intel
Driver Version
9.2.0.1013, 9-16-2010
Driver
c:\windows\system32\drivers\usbehci.sys
Intel(R) 6 Series/C200 Series Chipset Family USB Enhanced Host Controller - 1C26
Interface
PCI
Location
PCI bus 0, device 29, function 0
Type
USB EHCI Controller (USB 2.0)
Class
0Ch:03h:20h
PCI Identification
Vendor Name
Intel Corporation
Vendor ID
8086h
Device ID
1C26h
Revision
05h
Driver Provider
Intel
Driver Version
9.2.0.1013, 9-16-2010
Driver
c:\windows\system32\drivers\usbehci.sys
Renesas Electronics USB 3.0 Host Controller
Interface
PCI Express x1
Location
PCI bus 4, device 0, function 0
Type
USB xHCI Controller (USB 3.0)
Class
0Ch:03h:30h
PCI Identification
Vendor Name
NEC Corporation
Vendor ID
1033h
Device ID
0194h
Revision
04h
Driver Provider
Renesas Electronics
Driver Version
2.1.27.0, 9-13-2011
Driver
c:\windows\system32\drivers\nusb3xhc.sys
Processors
Intel(R) Core(TM) i7-2670QM CPU @ 2.20GHz (CPU:0)
Name
Intel(R) Core(TM) i7-2670QM CPU @ 2.20GHz
Cores
4
Threads
8
Signature
206A7h
Family
6h
Model
2Ah
Technology
32 nm
Temperature
66 C
Performance
Max Qualified Speed
2.20 GHz
Max Turbo Boost Speed
3.09 GHz
Current Speed
2.79 GHz
Multiplier
x 28.0 (8 - 22)
Max Turbo Boost Ratio
x 31
Bus Speed
99.78 MHz
Features
MMX, PSE36, EM64T, SSE, SSE2, SSE3, SSSE3, SSE4.1, SSE4.2, AVX, AES, XD, VMX, IDA
Cache Summary
L1 Data Cache
4 x 32.00 kB
L1 Instruction Cache
4 x 32.00 kB
L2 Cache
4 x 256.00 kB
L3 Cache
6.00 MB
Core : 0
Temperature
65 C
Threads
2
Core : 1
Temperature
69 C
Threads
2
Core : 2
Temperature
67 C
Threads
2
Core : 3
Temperature
66 C
Threads
2
L1 Data Cache
Quantity
4
Level
L1
Type
Data
Size
32.00 kB
Associativity
8-Way Set-Associative
Line Size
64 bytes
L1 Instruction Cache
Quantity
4
Level
L1
Type
Instruction
Size
32.00 kB
Associativity
8-Way Set-Associative
Line Size
64 bytes
L2 Cache
Quantity
4
Level
L2
Type
Unified
Size
256.00 kB
Associativity
8-Way Set-Associative
Line Size
64 bytes
L3 Cache
Quantity
1
Level
L3
Type
Unified
Size
6.00 MB
Associativity
12-Way Set-Associative
Line Size
64 bytes
Memory
System Memory
Total Physical Memory
8.00 GB
Maximum Supported Memory
8.00 GB
Page Files
Total Size
7.90 GB
Page File c:\pagefile.sys
Location
c:\pagefile.sys
Size
7.90 GB
4096 MB DDR3 (1333 MHz)
Source
SMBIOS
Memory Size
4.00 GB
Memory Type
DDR3 (1333 MHz)
Memory Manufacturer
Hynix/Hyundai
Memory Part Number
HMT351S6CFR8C-H9
Memory Serial Number
3280B845
4096 MB DDR3 (1333 MHz)
Source
SMBIOS
Memory Size
4.00 GB
Memory Type
DDR3 (1333 MHz)
Memory Manufacturer
Kingston
Memory Part Number
9905428-045.A00LF
Memory Serial Number
3A2D9D10
Batteries
Main Battery
Battery Name
Dell
Manufacturer Name
SIMPLO
Type
LION - Lithium Ion
Battery Serial Number
1130
Designed Capacity Percentage
13
Current Charge Percentage
100
Current Charge
7.23 Wh
Full Charged Capacity
7.23 Wh
Designed Capacity
57.72 Wh
Voltage
12.41 V
Communications
Network Card - Intel(R) Centrino(R) Wireless-N 1030
Vendor Name
Intel Corporation
Serial Number
4C-EB-42-82-35-6B
Interface
PCI Express x1
MAC Address
4c:eb:42:82:35:6b
Adapter Connected
Yes
Current Speed
117.00 Mbps
IP Address
192.168.0.129
IP Mask
255.255.255.0
Gateway IP Address
192.168.0.1
DHCP Server
192.168.0.1
Adapter DHCP Enabled
Yes
Driver Provider
Intel
Driver V

Answer 1

Iqb,
Make a system restore point.
Start, control panel, device manager, Go to the USB Controller section and click the + sign. Go to each USB Root Hub. right click on it, left click uninstall.
Restart your computer. When you login, the new hardware wizard will reinstall everything. Please be patient, it could take up to 2 minutes.
Try the webcam and see if it works.
If no, then the webcam became detached from the motherboard, usually near the webcam
Rick