Get Sporadic crashes

Question

My system crashes about once a week (dreaded grey screen)
I pasted the crash report below if anybody can decifer this please let me know if you can find out the problem thanks:
Mon Sep 29 13:33:15 2008
panic(cpu 1 caller 0x000AED84): "Uncorrectable machine check: pc = 0000000000D21AB8, msr = 100000000010B030, dsisr = 00008000, dar = 00000000615A255C\n" " AsyncSrc = 0000000000000000, CoreFIR = 0010000000000000\n" " L2FIR = 0000000000000000, BusFir = 0000000000000000\n"@/SourceCache/xnu/xnu-1228.7.58/osfmk/ppc/trap.c:975
Latest stack backtrace for cpu 1:
Backtrace:
0x0009B518 0x0009BEBC 0x00029DD8 0x000AED84 0x000AF004 0x000B2AF8
Proceeding back via exception chain:
Exception state (sv=0x62a08500)
PC=0x00D21AB8; MSR=0x0010B030; DAR=0x615A255C; DSISR=0x00008000; LR=0xBEEF0202; R1=0x629677F0; XCP=0x00000008 (0x200 - Machine check)
Backtrace:
0x00D2196C 0x00D2554C 0x00D25938 0x00CE81FC 0x00CEA4E0 0x00CEB034
0x00CF0894 0x00D20DAC 0x00CCECF4 0x00376778 0x0037C1E0 0x0037C330 0x0008F804 0x0002C1C8
0x00024C94 0x000B2E4C 0x64617461
backtrace terminated - frame not mapped or invalid: 0xBFFFE8B0
Kernel loadable modules in backtrace (with dependencies):
com.apple.GeForce(5.3.0)@0xcb1000->0xd4bfff
dependency: com.apple.NVDAResman(5.3.0)@0x907000
dependency: com.apple.iokit.IONDRVSupport(1.5.2)@0x8ef000
dependency: com.apple.iokit.IOPCIFamily(2.4.1)@0x808000
dependency: com.apple.iokit.IOGraphicsFamily(1.5.2)@0x8c9000
Exception state (sv=0x75572500)
PC=0x91B9A438; MSR=0x0200F030; DAR=0x08456548; DSISR=0x42000000; LR=0x91BA1360; R1=0xBFFFE8B0; XCP=0x00000030 (0xC00 - System call)
BSD process name corresponding to current thread: WindowServer
Mac OS version:
9F33
Kernel version:
Darwin Kernel Version 9.5.0: Wed Sep 3 11:31:44 PDT 2008; root:xnu-1228.7.58~1/RELEASE_PPC
System model name: PowerMac7,3
0L
0L

Answer 1

What would be your guess about this report:
Wed Dec 31 19:00:38 1969
panic(cpu 1 caller 0x000AED84): "Uncorrectable machine check: pc = 00000000000ABAA4, msr = 0000000040009030, dsisr = 42000000, dar = 000000000003D4C2\n" " AsyncSrc = 0000000000000000, CoreFIR = 0000000000000000\n" " L2FIR = 0000000000000000, BusFir = 0000000080000000\n"@/SourceCache/xnu/xnu-1228.7.58/osfmk/ppc/trap.c:975
Latest stack backtrace for cpu 1:
Backtrace:
0x0009B518 0x0009BEBC 0x00029DD8 0x000AED84 0x000AF004 0x000B2AF8
Proceeding back via exception chain:
Exception state (sv=0x16f49c80)
PC=0x000ABAA4; MSR=0x40009030; DAR=0x0003D4C2; DSISR=0x42000000; LR=0x00246284; R1=0x16EBB1C0; XCP=0x00000008 (0x200 - Machine check)
Backtrace:
0x000000FF 0x00246FE4 0x0010A85C 0x000F0078 0x000E1948 0x000EDB48
0x000EF1B8 0x000F04D0 0x00246A0C 0x002566D8 0x00256A68 0x00106F24 0x000EA8FC 0x000D9A18
0x0030ABDC 0x000B2CC8 0x00000000
Exception state (sv=0x130b8a00)
PC=0x95614498; MSR=0x0000F030; DAR=0x0003D4C2; DSISR=0x42000000; LR=0x92191FEC; R1=0xBFFFD410; XCP=0x00000030 (0xC00 - System call)
BSD process name corresponding to current thread: lsregister
Mac OS version:
9F33
Kernel version:
Darwin Kernel Version 9.5.0: Wed Sep 3 11:31:44 PDT 2008; root:xnu-1228.7.58~1/RELEASE_PPC
System model name: PowerMac3,5
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I thought it would be RAM but I've tried every combination of the RAM, from 3 -512 in to just 1.
There is no pattern and I'm nearly at my wits end.