Hi Sheilab; Rimmer is giving you good advice, Yes do what he said in his post. You can also do this Open Internet Explorer - Go To > Tools > scroll down to > Internet Options > Click on the General tab > Delete Cookies > Files > Delete All Offline Content > Clear history > hit apply and Ok. You will notice that the history tab you can set the number of days to keep. I have mine set for 1 day, but you can set it for whatever you want. These are just web sites that you went to in that day, they are all temporary files taking up space. Removing any of the above will not hurt your machine in any way - It will make it run faster after removing all that junk.
Make sure that you are Defraging your computer on a regular bases, if not Go To > Start > All Programs > Accessories > System Tools > Disk Defragmenter > Click on the drive you want to defrag and click defragmenter. This might take a little time if you are doing this for the first time.
Make sure that you are going to Windows Update and downloading all the critical updates for your machine. These updates also include updates for Windows Media Player 8, Although 9 and 10 are out for Windows Media Player. You might want to think of upgrading to 9 or 10. This might solve your problem with Player 8 and Microsoft has worked most of the bugs out of the new players and work fine in xp. I have windows media player 10 installed on mine and works fine. Then of course you could download any player that you wanted, you don't have to use windows media player 8, you could download Quick Time, Real Player, or any of the other one's out their. I have Quick Time, Real Player and Windows Media Player 10 installed on my machine. If you just want WMP-8, then thats your choice but 9 and 10 have more and better features installed.
Let us know if you want to upgrade and someone in the form will help you with whatever questions you have.
Let us know if this fixed the problem or it still persists and someone in the form will be glad to help.