Somehting's Wrong Here

Something has changed on my system here at the office and I cannot figure out what the problem is. But somehow the computer has stopped showing my quicktime films and somehow not being able to view the Q-times is messing up being able to download the broadcasts I have been doing with Ustream.tv. I have been down loading a lot of programs especially programs for things like converting video from one format to another and a couple of months I got rid of Quicktime in a fit of anger and after a couple weeks after I had cooled down I tried to re-install Quicktime but now QT would not load unless I have the dreaded Windows XP Service Pack II. I really don’t know how many times I have tried to install this patch or whatever Service Pack is but my system has never recognized the software and I can no longer run Quick-time movies. This non-file recognition has not been a problem until this morning when I tried to view a couple clips I took on my way into work and all I got from the play back was the audio and audio is so lame after one has had video. What really worries me and my mind always comes back to the thought is I may have down loaded a virus which is slowly occluding my system from working the way it should. I also worry that if in fact my system is infected I will have to call state IT in and the will have to “nuke” my system and start over. Not only is this time consuming but also way embarrassing.