OK, then this will become a technical bughunt through your computer....
I'll try to help, but without physical access to the computer I can't promise we'll find the cause (although since I've done this often before, the chances are good).
First, I'll need to know a bit of technical data of your computer, especially the following:
CPU speed, RAM size, Windows version, and a list of the installed programs (bestwould be a screenshot of the list from windows).
You can send them to me as a PM if you don't want to post that data for all to see.
Or (because I'm not an official helper) you can try to contact tech people of your choice - the cause is most likely either a damaged/overloaded windows or a background program other than the antivirus blocking the program.