Problems with MP3 players & TV

Hi,

I'm having problems with playing MP3 files: whenever I launch a program or do something requiring CPU time MP3 files are heavily disturbed . The same thing happens with my digi-TV (USB connection, using antenna).
I tried out two different MP3 players (iTunes and dBPowerAmp) and I checked the priority status of the players which was "high".

My guess is that this problem is due to optimizer programs I have used to speed up my XP. It seems that the XP works somewhat faster (which is fine) and it also seems that whenever a new program is launched almost all the CPU time goes to implement the task and hence leaves the MP3 player and TV without adequate resources. I tried to undo changes using the recovery points (they might be called differently in English since I'm using the XP in my native language) but unfortunately my cleaning programs had cleaned away almost all recovery points; of course, it was my own mistake.

What should I do? Should I change CPU settings? If so, how? Any other ideas?
Help would be greatly appreciated.

Regards,

Antti
Finland