Question : tried to upgrade to svc pk 3, now it won't boot

    I have a PC that has Windows Media Center 2005. Two nights ago I upgraded it from service pack 2 to service pack 3. During the upgrade, it hung for several hours. So I left it running overnight, thinking that by morning it would be done.
     The next morning I found out the PC had restarted and now it won't boot. Instead it just hangs at that screen that has that status bar at the bottom (and the status bar moves really slow).I also tried booting to Last Known Good Configuration but I get the same thing. I try to boot to safe mode and I get a blue screen. I don't think it finished the upgrade and now the PC is screwed up.
     The PC had Norton 360 (version 3.0) but stupid me, I didn't disable it during the upgrade. I think that's what caused it to not finish it (after doing some research on it yesterday I THEN found out I probably  should have disabled it first).
     I also cannot find the Windows CD that came with it (so I guess I can't run checkdisk on it).
     When I plug the hard drive into another PC I can still access the files.
     Is there any way I can fix Windows without having the Windows CD?

Answer : tried to upgrade to svc pk 3, now it won't boot

Beg or borrow an xp cd. Any version will do. Boot the cd and select repair from the menu to get to the recovery console. Because the sp3 install was corrupted, you need to remove it first. Follow the steps outlined here:

http://support.microsoft.com/kb/950249

Scroll down to Method 4:Recovery Console  Print out the entire page first if possible so you have the instructions in front of you. There are not many steps, but you need to do them in order.