Stability problems

Ok I have a small problem normally I have my pc overclocked to 675MHz 150MHz Fsb (P3 600EB) But recently I have put it back to normal, after having problems with my modem switches off when using kazaa over long periods of time 3-48 hours roughly. Now with it back to a 133MHz fsb my modem doesn't switch of using kazaa but just seems to stop internet activity and so kazaa disconnects. Also I've been having several more blue screens of death then usual(normally none or 1 or 2 a month sometimes). The main reason I put it back to 600Mhz is because soon I'll be building myself a new system and this pc will be going to my parents and it will be using the onboard sound and not my Videologic sonicfury card thats in at the moment.

Also in my new system I have decided what I'll be getting now except I don't know whether to get a GF4 4600 or a Ati 9700pro I know the Ati is a faster card but is it worth the extra cash it will be going with either a 2.66Gig P4 or If prices drop enough maybe a 2.8, when does the new nvidia card come out is there a fixed date or is it way of because then the Ati9700 will drop in price and so it might be better keeping my GF2ti and putting my Ati rage 128 in my current comp and then when I have the new graphic card put the GF2 back in my parents new machine

Anyways guy thanks for your help