Hardware update, problem solved?

I have been posting for about 6 weeks regarding my computer which would shut down while performing certain tasks (Installation of windows xp sp2, 'Limewire', etc). No warning, just complete loss of everything like I unplugged it from the wall. Right before it would shut down, there would be a sound that got louder and louder, then *click-beeeeeooouuuuu*...off. So, I unplugged my 40 gig hard drive which is almost 3 years old (maxtor that came with a dell which I removed and put in a custom one). Now, after unplugging it, no problems installing sp2 or with anything else for that matter. I know through testing that Limewire and sp2-installation were the elements that caused shutdown, also my limewire was saving the downloaded files to my 40 gig drive that is now removed.

Does this make sense? I thought it might be a mobo problem, but it looks like this is not the case, thank the lord. Anyway, lemme know if this is a reasonable assumption or if my hopes of a 'fixed' computer are in vane

-Joe

P4 prescott 2.8GHz, 800fsb, 1Gb cache
1 stick 512mb PC3200 ddr
160Gb seagate HDD 7200 rpm
***40Gb maxtor HDD 7200 rpm (problem source I think)
cd-rw drive
dvd +/-r drive
floppy drive
ATI Radeon 9800 pro agp 8x
PCI modem
On-board LAN (in use)
MOBO-ASRock P4S61
500W mad-dog surge/short-circuit protected PSU

 

Of course