Hi, I have recently rebooted my PC with xp OS. I have installed kaspersky anti virus program.
But, the problem is my system is getting slow while I try to open other applications when already one is running. I am experiencing a this problem when song are played and other applications a re opened meanwhile . Give me a solution.

Defragging
START > RUN > msconfig > STARTUP - uncheck programs that load at startup to reduce overhead (read carefully)
Uninstall truly unnecessary programs altogether
Install more memory (ALWAYS a great performance idea) - how much memory do you have anyway?
Make sure you don't accidentally have more than 1 antivirus program or firewall installed