Whenever I would open up a folder that contains media files, the folder would automatically close and for several seconds, I can't see the taskbar. After a few seconds, I could see everything. Does anyone know what what is causing it and how to fix it? Thanks.

If this is a new problem try a system restore to a point prior to the problem.

start > All Programs > Accessories > System Tools > System Restore

If that doesn't help I suggest following the advice here:

http://www.techhelpforum.com/showthread.php?t=3702

Then post your log in that section of the forum.