Everything goes black (MAC PRO Early 2009 problem)

[trollking]

So there I am minding my own business, playing a little bit of the Warcraft. Then click everything goes black. Both my monitors go black, audio stops basically everything just shuts down but there is still power to the computer and the fans are still spinning but everything else is down. I have to hold the power button down to restart the computer. Everything comes back and I get this message:

Interval Since Last Panic Report: 1618282 sec
Panics Since Last Report: 2
Anonymous UUID: 6F6B39E6-6BD8-4399-BDB3-6F00A147400C

Mon Mar 15 21:14:59 2010
panic(cpu 6 caller 0xa91b10): NVRM[0/1:0:0]: Read Error 0x00000100: CFG 0xffffffff 0xffffffff 0xffffffff, BAR0 0x92000000 0x8a310000 0x0a0180b1, D0, P2/3
Backtrace (CPU 6), Frame : Return Address (4 potential args on stack)
0x89e13c38 : 0x21b2bd (0x5cf868 0x89e13c6c 0x223719 0x0)
0x89e13c88 : 0xa91b10 (0xc7bfec 0xce49c0 0xc87660 0x0)
0x89e13d28 : 0x15de90d (0x12001404 0x1243b004 0x100 0x6d28)
0x89e13d68 : 0x1655089 (0x1243b004 0x100 0x64 0x0)
0x89e13e98 : 0xb97934 (0x1243b004 0x11c4d804 0x0 0x0)
0x89e13ec8 : 0xa9a1fb (0x1243b004 0x11c4d804 0x0 0x0)
0x89e13f08 : 0x5491b5 (0x0 0x12b7c100 0x1 0x29c50a)
0x89e13f58 : 0x5481e6 (0x12b7c100 0x863ea0 0x0 0x2a0596)
0x89e13f88 : 0x548640 (0x11e62500 0x11739d40 0xffff09f5 0x0)
0x89e13fc8 : 0x29d68c (0x11e62500 0x0 0x10 0x0)
Kernel Extensions in backtrace (with dependencies):
com.apple.nvidia.nv50hal(6.0.6)@0x14d3000->0x1959fff
dependency: com.apple.NVDAResman(6.0.6)@0xa33000
com.apple.NVDAResman(6.0.6)@0xa33000->0xce5fff
dependency: com.apple.iokit.IOPCIFamily(2.6)@0x940000
dependency: com.apple.iokit.IONDRVSupport(2.0)@0xa25000
dependency: com.apple.iokit.IOGraphicsFamily(2.0)@0xa07000

BSD process name corresponding to current thread: kernel_task

Mac OS version:
10C540

Kernel version:
Darwin Kernel Version 10.2.0: Tue Nov 3 10:37:10 PST 2009; root:xnu-1486.2.11~1/RELEASE_I386
System model name: MacPro3,1 (Mac-F42C88C8)

This is not the first time this has happened. getting more frequent actually. Any help would be much appreciated, even just insight into what could be causing the problem.