It is ctrl-alt-delete not alt-cont-delete. But even using those keys will only open Task Manager, then you have to end a process when you are in there, it doesn't stop something just pushing those keys.
You are using an out of date version of
HiJackThis. Remove that one and download the newest version which is 2.0.2
Even with this scan with the older version I don't see anything bad on there. Have you removed all your temp files, done a defrag lately?
Have you just rebooted the computer?
How big is your hard drive and how much space is remaining? How much RAM do you have installed?