It sounds to me like your computer is busy with other programs and doesn't have enough memory/CPU available for the media player. Are you running other memory/CPU intensive tasks?

If this is not the case, I would suggest that you take steps to clean up your computer. Computers run slower the longer you have them. Why is this? There are stray files, etc. that clog up your computer's arteries, so to speak, and need to be eliminated. I would recommend using a registry cleaner to begin with. If that doesn't help, you may have malware on your computer. Viruses, worms, spyware, etc. can definitely slow down your computer. Run some scans with antivirus and antispyware applications.

Good Luck

Dano