Ok, where to start...

The problem first arose when my G5 (Dual 2Ghz) froze on me. No "Force quit" would help me out, so had to resort to holding in the power button to switch off the machine.
After that OSX wouldn't boot up, I just kept getting the blank blue screen.
I took my Mac to my local store and they said that it was probably a hard drive issue. Luckily i have two hard drives, so I did a fresh install of 10.4 onto my backup drive and salvaged what i could off my original drive.

Now my backup drive is experiencing the same problem... Freezing up on me and also some of the graphics are now corrupted (ie: icons on the desktop turning into a hotch-potch of colours).

I am starting to believe that this isn't a hard drive issue at all, but something else... CPU, Motherboard, Graphics card etc..
Or could it be a problem within one of the transfered files? Surely that can't corrupt an entire operating system (can it)?

Can any Mac genius out there help me??? I am at my wits end!

On the most recent crash i saved the error report. I don't know if it will help:-

panic(cpu 1 caller 0x000E13F0): vfs_drt: entry summary count > 0 but no bits set in map
Latest stack backtrace for cpu 1:
0x000954F8 0x00095A10 0x00026898 0x000E13F0 0x000E03F4 0x000DFA68 0x0023A7F4 0x00231FE8
0x000E4844 0x002320B8 0x000F9804 0x000EC884 0x000E8F64 0x000EC8D0 0x002ABDB8 0x000ABD30
Proceeding back via exception chain:
Exception state (sv=0x4F996A00)
PC=0x9003BF6C; MSR=0x0200F030; DAR=0xE0006000; DSISR=0x42000000; LR=0x00002FE0; R1=0xBFFFFD80; XCP=0x00000030 (0xC00 - System call)