well I'm not a techie however I have had similiar (and worse at times)problems with same operating system which stemmed from using wmp. I reccomend to not use it b4 and during running sensitive programs such as games and downloads(especially filesharing programs, which will multiply the problem especially Imesh).
If you do find a fix for it please post however so far that has been my remedy for it.
P.S. 9.0 is out already however I have not tried checking it for bugginess
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