Power Mac G4 (FW800) freezes often, with an occasional kernel panic

Question

I recently purchased a Power Mac G4 (FW800) on eBay for $160, minus a hard drive and stock video card, along with a hard drive cage.
Since I opened the box it came in late Saturday night, the lovely machine has constantly stalled, crashed, and for a while, I received kernel panics left and right-in fact, I had one today, but it was the text version (unlike the visual kernel panic, which is the kernel panic seen in OS X 10.2+, and I have 10.4.11 running on this machine).
Often, if I multitask, import music on iTunes, or do intense activity, it freezes.
To solve the problem, I have done multiple memory tests, have performed disk checks (verified disk permissions and have verified the disk itself, and have done repairs on the disk), have swapped RAM for more stable ram (I was getting a RAM error for a while with some generic RAM).
I would hate to sell the machine for parts, but if worse comes to worse, that may be the route I may go under. Is there anything I could do to avoid having to go that route? From the inside, all of the motherboard capacitors look fine, but I haven't checked the graphics card yet, but I doubt that's the culprit. I want to see if I could push my luck with Apple sending the AHT for the Power Mac, since I can't find any on eBay, but I'm working with a vintage Mac here, and this is New York, so my luck may be out.
Interesting, I installed iStat, and it has been giving me misleading readings. It says my CPU is at over 1000ºC, when I know through Temperature Monitor that the CPU is around 100º-110ºF and rarely goes above 115ºF.
There are some things I haven't tried yet:
1) Buying actual 2.5v RAM. That may hopefully be the key.
2) Removing the USB card I put in, along with my Broadcom-equipped Belkin Wi-Fi card I put in.
3) Calling Apple and begging them to send me a copy of the AHT for the Power Mac, and with that, hopefully, a copy of the system software.
Any suggestions? Comments? If need be, I'll post the system/crash logs for you hardware junkies.
System stats:
Power Mac G4 (FW800)
1.0GHz PowerPC G4 on a 133MHz bus
1GB PC2100 DDR SDRAM (originally had some PC3200 in the machine).
120GB Seagate HD
Stock Phillips CD-RW/DVD-ROM Combo
Pioneer DVD-111D (the nice DVD burner I cannibalized off my beautiful homebuilt Wine-doze PC)
Belkin 54g 802.11g Wi-Fi card
Masscool XWT-MTU25 USB 2.0 card
So far, I have removed iStat, have gone ahead and pulled out the USB card. We'll keep fingers crossed.

Answer 1

Did both, and I still freeze up when importing iTunes songs. I'll include some kernel panic logs for reference, for you techies.
1) Thu Nov 27 22:42:50 2008
panic(cpu 0 caller 0x00260820): fg: being freed with bad fg_count (32548120)
Latest stack backtrace for cpu 0:
Backtrace:
0x000954F8 0x00095A10 0x00026898 0x00260820 0x0025E95C 0x0025E730 0x002ABDB8 0x000ABD30
0x00000000
Proceeding back via exception chain:
Exception state (sv=0x3C240780)
PC=0x90014BEC; MSR=0x0200D030; DAR=0x00424000; DSISR=0x42000000; LR=0x907C9088; R1=0xF007C240; XCP=0x00000030 (0xC00 - System call)
Kernel version:
Darwin Kernel Version 8.11.0: Wed Oct 10 18:26:00 PDT 2007; root:xnu-792.24.17~1/RELEASE_PPC
2) Tue Nov 25 20:21:06 2008
Unresolved kernel trap(cpu 0): 0x600 - Alignment DAR=0x0000000002DDCC3D PC=0x00000000000A43C0
Latest crash info for cpu 0:
Exception state (sv=0x2DAF7280)
PC=0x000A43C0; MSR=0x00009030; DAR=0x02DDCC3D; DSISR=0x000000A0; LR=0x0001DEAC; R1=0x17773C10; XCP=0x00000018 (0x600 - Alignment)
Backtrace:
0x0001DE68 0x0001F47C 0x00024224 0x0002407C 0x00049878 0x00029234
0x000233F8 0x000ABEAC 0x3B2F6B65
Proceeding back via exception chain:
Exception state (sv=0x2DAF7280)
previously dumped as "Latest" state. skipping...
Exception state (sv=0x2DEEF780)
PC=0x9000B348; MSR=0x0000F030; DAR=0xA0B8C068; DSISR=0x0A000000; LR=0x9000B29C; R1=0xBFFFC630; XCP=0x00000030 (0xC00 - System call)
Kernel version:
Darwin Kernel Version 8.11.0: Wed Oct 10 18:26:00 PDT 2007; root:xnu-792.24.17~1/RELEASE_PPC
panic(cpu 0 caller 0xFFFF0006): 0x600 - Alignment
Latest stack backtrace for cpu 0:
Backtrace:
0x000954F8 0x00095A10 0x00026898 0x000A8204 0x000ABB80
Proceeding back via exception chain:
Exception state (sv=0x2DAF7280)
PC=0x000A43C0; MSR=0x00009030; DAR=0x02DDCC3D; DSISR=0x000000A0; LR=0x0001DEAC; R1=0x17773C10; XCP=0x00000018 (0x600 - Alignment)
Backtrace:
0x0001DE68 0x0001F47C 0x00024224 0x0002407C 0x00049878 0x00029234
0x000233F8 0x000ABEAC 0x3B2F6B65
Exception state (sv=0x2DEEF780)
PC=0x9000B348; MSR=0x0000F030; DAR=0xA0B8C068; DSISR=0x0A000000; LR=0x9000B29C; R1=0xBFFFC630; XCP=0x00000030 (0xC00 - System call)
Kernel version:
Darwin Kernel Version 8.11.0: Wed Oct 10 18:26:00 PDT 2007; root:xnu-792.24.17~1/RELEASE_PPC