ok, none of your components is old enough to present that kind of problems (mine are much older and work fine
)
now, let' s go to round 2:
do you have any second HD you can use as replacement of your 200 GB Maxtor? if you do, you should try it and see if the system becames stable and if that happens, then you got a defective HD - it is in warranty, isn' t it? i once bought a 4,3 GB (very long time ago) that in less thatn a month bega to act strange (not detected by the board and when detected my system crush without warning a few time after) so i went back to the store, returned it and got a new one and problem solved.
of course in your case, you' ll probably lose everything you have in there, so i think you' ll hope the problem to be something else.