Windows strange behavior (mouse won't click)

Windows 7, 64 bit

I think this started the other day when I accidentally dislodged the power cable to my hard drive (I don't have the side back on my tower yet ). I had to do a repair which sort of fixed the problems I caused, but not quite. Now my mouse only intermittently works. Sometimes I'll be able to minimize/maximize/close windows, click in text entry windows, click on buttons... (in other words, normal behavior), then, without warning, the mouse will be unable to do any of the above. I can still navigate between windows with alt-tab and tab and enter works sometimes to activate buttons, but the mouse has no effect on text entry windows, buttons... I have to ctrl-alt-del and the mouse usually will work there to restart the computer. I ran a Malwarebytes scan and scanned my whole system for viruses (Panda AV Free). I did a checkdisk, tried to repair with the Windows 7 disk. I am working to back up my computer because I fear I will have to reformat. Is there anything else I should try before getting that drastic? I'm pretty sure it's not a mouse issue (like dead battery or something) because the mouse moves around the screen, clicking the button just has no effect. Sometimes if I wait a few minutes it will start responding normally for a few minutes.