Panic crashes, what now?

Question

I keep getting panic crashes and from the log it looks like it's being caused my the graphics card. But I don't know what to do to fix it. Can it be fixed through the software? Like reinstalling graphics drivers? Mac is much different than Windows, so I don't quite understand how drivers work on Macs. The computer is an Intel iMac (white, not the newer silver).
Here is the log:
panic(cpu 1 caller 0x00381561): synchronizeGART::NvRmUpdateContextDma failed
Backtrace, Format - Frame : Return Address (4 potential args on stack)
0x147bb9e8 : 0x128d0d (0x3cc65c 0x147bba0c 0x131f95 0x0)
0x147bba28 : 0x381561 (0x9166c8 0x147bba9c 0x1 0x30b2000)
0x147bba48 : 0x8e24c1 (0x9166c8 0x2 0x2 0x147bba9c)
0x147bbab8 : 0x8e1f85 (0x30b2000 0x3318f80 0x3470510 0x2)
0x147bbb38 : 0x9017ee (0x30b2000 0x3318f80 0x3470510 0x0)
0x147bbb68 : 0x8e0ee7 (0x30b2000 0x3318f80 0x3470510 0x0)
0x147bbb98 : 0x9017ba (0x30b2000 0x3318f80 0x3470510 0x121acf)
0x147bbbb8 : 0x8df4de (0x30b2000 0x3318f80 0x3470510 0x1207eb)
0x147bbbd8 : 0x901819 (0x30b2000 0x347050c 0x0 0x0)
0x147bbbf8 : 0x8e714b (0x30b2000 0x347050c 0x147bbc28 0x90068e)
0x147bbc28 : 0x8fcee4 (0x3470400 0x347050c 0x80 0x3bf3e9)
0x147bbc78 : 0x8e7c98 (0x3470400 0x0 0x0 0x0)
0x147bbcf8 : 0x3b19b9 (0x3470400 0x0 0x147bbd2c 0x147bbd28)
0x147bbd38 : 0x3b4e75 (0x3470400 0x0 0x2dcf010 0x1)
0x147bbd68 : 0x189fdc (0x3470400 0x0 0x2dcf010 0x2eb02c0)
0x147bbdb8 : 0x12b4ee (0x2eb028c 0x2eb08a0 0x147bbdf8 0x11e042) Backtrace continues...
Kernel loadable modules in backtrace (with dependencies):
com.apple.GeForce(4.5.6)@0x8d1000
dependency: com.apple.iokit.IOPCIFamily(2.2)@0x5bb000
dependency: com.apple.iokit.IOGraphicsFamily(1.4.8)@0x6ab000
dependency: com.apple.iokit.IONDRVSupport(1.4.8)@0x6c6000
dependency: com.apple.NVDAResman(4.5.6)@0x6d5000
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: iMac6,1, BootROM IM61.0093.B07, 2 processors, Intel Core 2 Duo, 2.16 GHz, 1 GB
Graphics: NVIDIA GeForce 7300 GT, NVIDIA GeForce 7300 GT, PCIe, 128 MB
Memory Module: BANK 0/DIMM0, 1 GB, DDR2 SDRAM, 667 MHz
AirPort: spairportwireless_card_type_airportextreme (0x14E4, 0x87), Broadcom BCM43xx 1.0 (4.170.46.9)
Bluetooth: Version 1.9.5f4, 2 service, 0 devices, 1 incoming serial ports
Serial ATA Device: ST3500641AS Q, 465.76 GB
Parallel ATA Device: PIONEER DVD-RW DVR-K06, 743.56 MB
USB Device: Built-in iSight, Micron, Up to 480 Mb/sec, 500 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
USB Device: Hub in Apple Pro Keyboard, Mitsumi Electric, Up to 12 Mb/sec, 500 mA
USB Device: M4848, Logitech, Up to 1.5 Mb/sec, 100 mA
USB Device: Apple Pro Keyboard, Mitsumi Electric, Up to 12 Mb/sec, 250 mA
It would be nice if there was some way to get this problem fixed through software, rather than have to bring it to an Apple repair facility to replace the graphics card. But if replacing the graphics card is the only way to fix it, then I guess that's what I'll have to do.
But I figured I'd come here and ask if anyone knew a fix before I spent big money to get it repaired (no longer under warranty).
From all my searching I keep finding ways to find the causes of kernel panic crashes, but not what to do once I figure that it's the video card causing them.
Thanks for any help you can offer.
Sorry for the huge wall of text too...

Answer 1

Hi,
First thing to do is back up your files/images/video/audio if you haven't already done so.
You could try an Archive and Install using your restore disk(s) to see if that would help.
To reinstall Mac OS X:
Insert the Mac OS X Install Disc and double-click the Install Mac OS X icon.
Follow the onscreen instructions. In the pane where you select the destination disk, select your current Mac OS X disk (in most cases, it will be the only one available).
*Click Options. If you want to save your existing files, users, and network settings, select “Archive and Install,” and then select “Preserve Users and Network Settings.”* If you want to erase everything on your computer and reinstall Mac OS X, select “Erase and Install.” You can’t recover erased data.
Click Continue.
Click Customize to select which parts of Mac OS X you’d like to install, or click Install to perform a basic installation (recommended).
If you purchased a standalone version of Mac OS X, these installation instructions are in a booklet PDF file located on the Mac OS X Install Disc.
If you need to reinstall the version of Mac OS X that was on your computer when you purchased it, or if you need to restore all the software on your computer, including Apple, bundled third-party applications, and printer drivers, review the instructions in the manual that came with your computer.
Read here before performing an Archive and Install. Resolving Kernel Panics
Carolyn