keyboard stops responding for a few seconds, then resumes

Question

I have a Dell Inspiron laptop running Windows Vista (SP2). Recently the keyboard has developed an annoying habit of stalling every 15-20 seconds for around 3 seconds.

If I'm typing something or hitting a keyboard shortcut, in whatever application, my input is just ignored. After the 3ish seconds elapse, the keyboard springs back into life and anything buffered during those seconds is applied.

No input seems to be ever lost while the keyboard is unresponsive, but it's still incredibly frustrating.

During this time the mouse is movable, but the buttons don't respond.

The computer itself doesn't seem to stall - I can watch movies or listen to music without interruption.

I've had a look at procmon, procexp and MooO but nothing highlights anything unusual running. I've swapped virus protection from AVG to Avast on the off chance that it's something to do with that, but to no avail.

The only unusual thing I've done on the laptop recently was install Visual Studio 2010 Beta 2, but the problem didn't develop until a week or two after that so I don't think it's related.

Any help would be greatly appreciated.

Solution

The first thing I would suspect are hardware interupts. Try running Process Explorer. It will show you not only process & memory usage, but hardware and IRQs. Something may jump right out at you just by running this.

If you suspect a driver, i.e. keyboard driver, then this might help.

Comments

[tenpn]

No, it's the keyboard in the laptop.

[tenpn]

PCMservice.exe was scanning my contacts directory every few seconds. It's a dell multimedia video service, so I don't see why it needed to do that. Disabled it in msconfig and now the keyboard is fine. Only one type of program needs to scan my contacts directory :( but two full AV scans from AVG and from Avast didn't find anything so fingers crossed I'm ok.