Computer freezes when opening applications

. After running rkill, malwarebytes, hijackthis: my computer continues to freeze every time I open up an application. I can click the start button and browse through folders, applications extremely fast though.

 

I should also add that I get a single beep when I start up the computer.

 

It may be that windows files need checking, after using these tools, I suggest that you click Start, then run, then type in sfc /scannow, and put your windows disk in the dvd/cd rom drive, -if it starts up, just click exit, and watch the little window in the middle of your screen, as the check progreses- If it shows a retry box, click retry, and it will replace any damaged windows protected file, as it goes. It can take up to an hour depending on your specs of your machine.
In Vista, and Windows7, the run command is under accessaries.
The single beep is often a normal post beep.