Itunes won't sync iphone 3G

Question

itunes hates me lols. i've uninstalled/reinstalled itunes twice because itunes keeps telling me whatever is in my usb is not recognised but sometimes appears in my computer as a camera. finally, it is recognised and begins to sync my iphone 3G and then tells me that something is wrong and it can't be sync. then it appears that all my apps were deleted. i tried with my ipod nano (2nd gen) but itunes tells me it's corrupt and to restore and then doesn't let me to restore.
i don't know whether it's my hardrive, my computer, itunes, my iphone and/or ipod, the usb port, the usb cord. it's driving me insane that i don't know what specifically is wrong. i've tried everything >.<
this is what it said when i ran the diagnostic test
Microsoft Windows XP Home Edition Service Pack 3 (Build 2600)
Dell Computer Corporation Dimension 3000
iTunes 8.1.1.10
QuickTime 7.6
FairPlay 1.3.6
iPod Updater Library 8.1d19
CD Driver 2.1.0.1
CD Driver DLL 2.1.1.1
Apple Mobile Device 2.4.1.7
Apple Mobile Device Driver 1.40.0.0
Bonjour 1.0.6.2 (118.5)
iTunes Serial Number B22801E23C7***
Current user is an administrator.
The current local date and time is 2009-05-10 17:11:35.
iTunes is not running in safe mode.
Video Display Information
Intel(R) 82865G Graphics Controller
** External Plug-ins Information **
No external plug-ins installed.
** iPod/iPhone Connectivity Tests **
iPodService 8.1.1.10 is currently running.
iTunesHelper 8.1.1.10 is currently running.
Apple Mobile Device service 2.12.36.0 is currently running.
Universal Serial Bus Controllers:
Intel(R) 82801EB USB Universal Host Controller - 24D2. Device is working properly.
Intel(R) 82801EB USB Universal Host Controller - 24D4. Device is working properly.
Intel(R) 82801EB USB2 Enhanced Host Controller - 24DD. Device is working properly.
Intel(R) 82801EB USB Universal Host Controller - 24DE. Device is working properly.
No FireWire (IEEE 1394) Host Controller found.
Connected Device Information:
, iPhone 3G running firmware version 2.2.1
Serial Number: 83836VM**
Most Recent Device Not Currently Connected:
iPod nano (Second Generation) running firmware version 1.1.3
Serial Number: 7L636ZD**
** iPhone/iPod Touch Sync Tests **
One or more sync tests failed.
from what i can see, it's only the syncing that has failed. and i've done all the things apple says i need to do if syncing fails. HELP!
<Edited by Host>

Answer 1

One thing that might help out.
When your iphone is connected, on the summary screen, is the iphone set to sync automatically?
If not, you might need to drag and drop your music videos to the iphone.
If it is set to sync automatically, then go to the music tab and make sure the box is checked to sync music videos.
If it is, try right clicking(control click) on the iphone on the left of itunes under devices and reset warnings.
Now try to sync again and see if any error messages come up.
Hope this helps.