crazy problem

i have an odd problem with my computer where it seems to randomly start acting up the sund will get very scratchy the internet will get so slow its unusable and my TV-tunner card will start makeing lines across the picture. All these things seem to happen all at once and fairly randomly to. Its not a virus because i just reformated everything in hopes that it was. but the problem is still occuring. I have a built in sound card on a Nivida nForce mother board. an ATI tv wonder VE TV-tuner card and my networking port is also built into my mother board. Any help is apricated

Such thing is ussually a memory problem, have you overclocked the PC? Try replacing the memory-modules. It might help

What operating system you're using with ?, windows 98 have some problem with some Ati peripherals although not all of them, if so, have you update your Win98 OS ?

No im useing Windows XP.

yesterday i reset my BIOS to standard settings ( i think the problem may have started after i was playing with it to try to get an old game to work) and i havent had a problem yet but like i said before it seems completely random.

And Lightning, If above didnt fix it, no ive never overclocked my PC, and do i realy need to replace my memory cant i just scan it for bad sectors??

This problem probably caused by hardaware conflict or driver damage, if the hardware conflict its ussually clear with only clear the CMOS, but if still happens after you checked all the things such Memory, VGA, and Bios, the problem might caused by driver conflicting, so why don't you try to reinstalling the VGA and tV Tunner driver, if it won't work, You must re-install the OS, make sure you've backed-up important things.

Make sure your PSU (power supply unit) is properly earthed and connected to the case and Motherboard. This can often be the cause of many sound problems and my afect other gubbins.

UNPLUG IT FIRST THOUGH!

Let's know if somehow you made it Ok!
;)