Got a Problem

Howdy-I don't know if this is the right place to post this because I'm not sure what's happening.
When I started up my computer(that was working fine yesterday), it started clicking and beeping while it was booting up. Then the name of the disc drive was changed to "+++++++++". Address bars, search bars, windows functions including notepad started writing plus signs non-stop.
Virus and Adaware scans don't detect anything, HijackThis doesn't show anything unusual, but I can't run the Windows disc error checking program.
I got a bad feeling about this, can anyone give me any information while my computer is still running?
Thanks.

 

but I can't run the Windows disc error checking program.

Hmm, i know that some AV's does not allow to run a Windows disc check,
so which AV are you using ?

 

BitDefender9 Standard.
Something is going on other than that. For example, when I went to log in here(using Firefox), the computer began writing plus signs("++++++++++++++") in the user name login box. It does the same thing with the search box, and Windows boxes like "Run"(I tried to run msconfig to see if anything was there). If I open a text document, the computer starts writing plus signs in it.
I'm going to switch to IE6 and run a Bitdefender online scan. It sure looks like some kind of crapware designed to automatically overwrite stuff.
Not stoked at all.

 

Lots and lots of trouble, all caused by a bad keyboard. A PS2 keyboard I use just for troubleshooting and installing major hardware, now securely in the dumpster.