Recurring crashes and Disk errors

I have a
Gigabyte Motherboard GA-K8Nf-9
which has nforce4
AMD Athlon 64 3200+ 2.0GHz socket 939
2x512 MB DDR SDRAM DDR 400 (PC3200)
Geforce 6600GT PCIexpress
w/forceware verision 163.71.
driver version 6.14.0011.6371
2 SATA drives
2 IDE drives

I usually have XP on a SATA and linux on an IDE dual boot.
Problem is every 3- 6 months I've had the system lockup copying DVD's and playing FarCry and even during a 3D game on Linux. It's lockedup weekly with FarCry.
Most of the time it locksup, the drive with the OS gets corruped and wont start or wont boot. At least once I've lost partitioning and otherwise usually have to reload XP. When linux crashed the disk format was no longer recognized. If I am lucky only some corruption is repaired with chkdisk and XP still boots. Sometimes the system resets at the crash but lately with FarCry it just freezes and I have to pull the power. Sound is static or repeating - video is frozen and nothing responds.

I first got a new case and Powersupply thinking that might be it. I've run a memory test which comes out fine. I don't believe I have 3 unreliable HD's. When one SATA quits I load XP on the other. I'm getting tired of reloading XP and drivers - three times in 3 weeks plus linux. I loaded antivirus. I've tried a stress test with nTune but am not sure what it's doing? What is the problem?
I've posted the above elsewhere without response. After the latest crash I can't get XP to load (I'm running Linux now). I've setup sensors in Linux and get this:

k8temp-pci-00c3
Adapter: PCI adapter
Core0 Temp:
+18°C

it8712-isa-0290
Adapter: ISA adapter
VCore 1: +1.07 V (min = +0.00 V, max = +4.08 V)
VCore 2: +2.70 V (min = +0.00 V, max = +4.08 V)
+3.3V: +3.36 V (min = +0.00 V, max = +4.08 V)
+5V: +3.52 V (min = +0.00 V, max = +6.85 V)
+12V: +11.90 V (min = +0.00 V, max = +16.32 V)
-12V: -11.28 V (min = -27.36 V, max = +3.93 V)
-5V: -8.31 V (min = -13.64 V, max = +4.03 V)
Stdby: +2.07 V (min = +0.00 V, max = +6.85 V)
VBat: +4.08 V
fan1: 3183 RPM (min = 0 RPM, div = 8)
fan3: 0 RPM (min = 0 RPM, div = 8)
M/B Temp: +25°C (low = +127°C, high = +127°C) sensor = thermistor
CPU Temp: +20°C (low = +127°C, high = +60°C) sensor = thermistor
Temp3: +69°C (low = +127°C, high = +127°C) sensor = thermistor

The +5V looks odd. Also the northbridge is hot to touch but Temp3 never changes so I dont think it is reflected.