Intel iMac continuous crashes - cannot restart

Question

Computer has been running fine for the last 3 years (it has bootcamp running Windows).
Have not had a problem before with crashes. Was using it all day today, then a grey colour came down my screen and a message told me to +restart my computer. hold down the restart key.+
I did this and the computer restarted with an errorlog that i could send to apple - i did this and it worked fine for 10 minutes, then the same thing happened.
I kept restarting and sending the errorlogs to apple - and the crashes have kept happening. I have notcied that my Entourage application is now also unexpectadly closing down.
Now after about the 10th restart it just will not start at all - it comes up wiht a black screen and the error log appears on that.
*Here is a copy of one of the many error logs I receive:*
panic(cpu 1 caller 0x001A49CB): Unresolved kernel trap (CPU 1, Type 14=page fault), registers:
CR0: 0x8001003b, CR2: 0x00000000, CR3: 0x00ecd000, CR4: 0x000006e0
EAX: 0x3b9aca00, EBX: 0x00000000, ECX: 0x00000000, EDX: 0x00000000
CR2: 0x00000000, EBP: 0x2526bec8, ESI: 0x037a5e92, EDI: 0x00000000
EFL: 0x00010206, EIP: 0x0032cd79, CS: 0x00000008, DS: 0xe13b0010
Backtrace, Format - Frame : Return Address (4 potential args on stack)
0x2526bcf8 : 0x128d0d (0x3cc65c 0x2526bd1c 0x131f95 0x0)
0x2526bd38 : 0x1a49cb (0x3d2a94 0x1 0xe 0x3d22b8)
0x2526be48 : 0x19b3a4 (0x2526be58 0x2526be68 0xe 0x190048)
0x2526bec8 : 0x2ba5cc (0x2ba5d4 0x0 0x1 0x13546b)
0x2526bf58 : 0x2ba5fa (0x0 0x1 0x2526bf78 0x19e23a)
0x2526bf78 : 0x13d989 (0x0 0x0 0x0 0x0)
0x2526bfc8 : 0x19b21c (0x0 0x0 0x19e0b5 0x407ea10) Backtrace terminated-invalid frame pointer 0x0
Kernel version:
Darwin Kernel Version 8.11.1: Wed Oct 10 18:23:28 PDT 2007; root:xnu-792.25.20~1/RELEASE_I386
Model: iMac4,1, BootROM IM41.0055.B08, 2 processors, Intel Core Duo, 2 GHz, 2 GB
Graphics: ATI Radeon X1600, ATY,RadeonX1600, PCIe, 128 MB
Memory Module: BANK 0/DIMM0, 1 GB, DDR2 SDRAM, 667 MHz
Memory Module: BANK 1/DIMM1, 1 GB, DDR2 SDRAM, 667 MHz
AirPort: spairportwireless_card_type_airportextreme (0x14E4, 0x89), Broadcom BCM43xx 1.0 (4.170.46.9)
Bluetooth: Version 1.9.5f4, 2 service, 0 devices, 1 incoming serial ports
Network Service: Built-in Ethernet, Ethernet, en0
Serial ATA Device: Maxtor 6L250M0, 233.76 GB
Parallel ATA Device: PIONEER DVD-RW DVR-K05
USB Device: Built-in iSight, Micron, Up to 480 Mb/sec, 500 mA
USB Device: Hub in Apple Pro Keyboard, Mitsumi Electric, Up to 12 Mb/sec, 500 mA
USB Device: Apple Optical USB Mouse, Mitsumi Electric, Up to 1.5 Mb/sec, 100 mA
USB Device: Apple Pro Keyboard, Mitsumi Electric, Up to 12 Mb/sec, 250 mA
USB Device: Bluetooth USB Host Controller, Apple, Inc., Up to 12 Mb/sec, 500 mA
USB Device: IR Receiver, Apple Computer, Inc., Up to 12 Mb/sec, 500 mA
If anyone knows a solution I would be most grateful - I need ot get this sorted asap.

Answer 1

Try following this procedure to reset SMC
http://support.apple.com/kb/HT1543
which is basically disconnecting all cables and power, and reconnecting following a precise procedure. If you are connecting into a crowded or old power strip (surge suppressor), try connecting it directly to the wall outlet, at least initially (as a test). Power it up with nothing connected, except for the power cord. If that works properly, connect just your keyboard/mouse and use it that way for a while, to make sure it continues to work properly.
If the same issue occurs, even with nothing connected, you'll have to look at other causes.
To see if it might be software, insert your Mac OS X installation disc and restart with C key held down to start up from the optical drive. Does it get to the Installer screen without crashing? If so, it may indicate some problem with your currently installed system.
If it still crashes, one thing you can try is removing your RAM modules and reinserting them into their slots. While you are looking at the bottom edge of the iMac, wipe off the dust on the air intake vents; I added some RAM recently, and I was amazed at how much dust there was on those vents, blocking airflow.