Problems loading Win XP with SP2

First of all, here are my computer specs -

CPU - AMD Athlon 1.1 GHz
Motherboard - Gigabyte GA-71XE4
Memory 768 MB PC133 SDRAM (3 x 256mb)
Hard Drive 60GB Maxtor 96147H6
Lite-On DVDRW SOHW-1693S
NEC DVD+RW ND-1100A
Video Card - ATI All-in-Wonder Radeon 32 MB DDR
Sound Card - Creative SoundBlaster Live!
Modem - Lucent 56K V.90 Winmodem
Keyboard - Multimedia keyboard (PS/2)
Mouse - Microsoft IntelliMouse

This machine is old and came installed with Win ME. Having had enough of that crappy OS, I upgraded to Win XP Home. This worked fine until I tried to upgrade again to Win XP Pro. I bought OEM software for this and when installing Windows the installation stopped half way through. I managed to reinstall XP Home eventually. This didn't stop me trying another copy of Win XP Pro with SP2 which installed fine then after the first reboot froze at the Windows logo screen.

I reinstalled XP Home again but when trying to update to SP2 again experienced freezing at the Windows logo screen. Having spent many hours trying to resolve this issue I finally got the OS working with all available updates. I read the 'Read and run' thread on spyware/malware/viruses etc. and went through all the steps. This I thought would be the end of my problems with the system but I was wrong.

Having experienced difficulties in reading DVD's (the read time had gone from 30mins to 180mins), and having tried various ways to correct this problem I decided to do a fresh install of XP Home. Again, when updating to SP2
the system froze.

I'd exhausted the steps in 'Read and Run' section so I looked on the net for other solutions. It became clear I'd probably corrupted files and the hard drive. I thought it would be a good idea to wipe the hard drive completely
or try FDISK /MBR but I read a report:

http://www.cknow.com/articles/38/1/FDISK-{47}MBR

which said not to use FDISK /MBR which left me clueless as to what my next step should be.

I've also seen programs like KillDisk and Dban mentioned but I'm worried I could cause even further damage, especially if I wipe the MBR.

I'm not sure if this is the correct forum but if anybody can help me with this it would be appreciated as I've had enough installing, reinstalling for a lifetime???