Slow response when opening .txt file

I cannot open a .txt file, the computer acts like it wants to open the file but it never does. Not only am I getting slow responses but I can’t even right click and go into properties. I have tried to open notepad and I get the same slow response and it never opens. I have reinstalled windows SP2 but that didn’t help either.I ran a virus scan and it came back clean. What could possibly be causing this to happen?