I guess I was bragging too much to my PC user friends about never having a problem with my iMac and jinxed myself. The other evening I get the usual 'update available' message for Safari and Quicktime so I went ahead and updated them as easily as it always was. The next day I noticed that I can not open QuickTime movie files with Quick Time ( the default ) or WMV if I switch to that , clips I had saved and viewed plenty of time but get a MAC OS ERROR -50 I read that Perian was the 'fix-all' but that didn't do anything . I have been online with 'Get Answers' also for two days and they seem to think it's a codec problem that can be fixed easily ... though I haven't heard anything else on what to do from them yet. They also suggested Perian and seems that when that didn't work it threw a wrench in their gears ... I'm hoping this can be remedied with someone talking me through it as my MAC dealer I bought this from went out of business ... and there is no others close by. Am I looking to send this out for a repair or is this something simple I can fix here at home if I get the right help. ???