When hard drive used PC shuts OFF

So I got a Rootkit UAC trojan which wreaked havoc on my hard drive. I went through the uninstall but what happens is when windows xp pro starts off with that drive, the computer TURNS OFF like you pulled out the plug from the wall...no shut down or anything.

So I installed a new hard drive, re-installed windows, and then connected the old hard drive....when it is accessed through win xp it shuts the pc down...if I use a live cd version of linux, i can access the drive and start copying some files, but STILL the pc will shut off after a few minutes of copying files...the files do make it over to the new drive up to the point of the shut off.

My last option is I want to try a SATA to USB adapter and take the drive out of the pc and see if that works. All the data is still there on that drive.

Has anyone else had this problem before? Any other ideas on what to try? Also, if I try to start win xp pro in safe mode with that drive connected, it freezes as the various programs are loading.

My pc is a custom built:

Windows XP Professional Service Pack 2 (build 2600)
2.00 gigahertz AMD Athlon 64 X2 Dual Core
Board: Gigabyte Technology Co., Ltd. GA-M55SLI-S4
1024 Megabytes Usable Installed Memory
NVIDIA GeForce 7600 GS [Display adapter] (2x)

Thanks for looking.