Z Lag Problems

My Z11 is lagging.
At first it was just Firefox, but now my volume and screen brightness keys are lagging as well.

I have checked out all of my startup programs, my thermal strategy, power options, defragged the HD, the registry, run TuneUp Utilities, virus scan, Spybot, etc.
I can't seem to figure out the root of the problem.
This has come about all of a sudden, and it's getting worse.

I'm not really sure what I can provide, so basically, tell me what I'm either doing wrong, or what I have to do to get this fixed.
If you think I should wipe the HD and reinstall Win7, fine.
I have 212GB free at the moment, for the record, so I don't think that'd be an issue.
I do have a lot of files I can get off of it, though (lot of concerts).

Anyway, I'm at a loss as what can be wrong right now.
Please, if you can help, I'm all eyes.