This kinda thing happens to me. The best thing to do (i find) is to open stuffit expander (if u dont have it u can get it for free at download.com or versiontracker.com) and go to file > open and select the file u want to open, it should decompress the file easy (unless its an .exe file obviously). For .mp3's, simply open itunes and select Advanced > Convert to Mp3 and the mp3 will be "converted" and added to your music library. For Quicktime Movies, again open up the file using quicktime (file > open) easy as that. remember, if its an application file (like an mp3 to itunes or .mov to quicktime), go into the most relevant application and open it up using that, if its a compressed file (ie. a .sit or .zip etc) then open it up ussing stuffit expander or whatever decompression software u have. have fun.

ps. do u have any problems with error type 3's and limewire? I do BIGTIME, maybe u got an extension r sommat that i dont, if ya could, would ya shove sommat on my thread "ERROR TYPE 3" cos its driving me nuts.