Question : Laptop keyboard randomly types wrong characters.

I've had this perplexing issue for quite some time now.  It originally started when I had Windows XP on my Latitude D830, that randomly within certain programs, usually Office, my keyboard would type random letters or numbers.  I could hit the "S" key and get an "X" the one time and "7" the next.  I've checked the regional settings and those are correct, and also checked my laptop thourghly for any malware and have found nothing.  What was strange is that my Vista Desktop also had this problem for a little while which made me think it had to be malware, but I've scanned both machines inside and out with ZoneAlarm and Malwarebytes and both are kept completely up to date, although I haven't noticed it on the desktop recently.

I did some troubleshooting with Dell tech support and at first they replaced the keyboard, in addition to this I upgraded to Windows 7 Pro which wipes the hard drive on an XP upgrade, so that would have removed any thoughts of it being a virus, right?  And just yesterday, Dell replaced, the motherboard, palm rest, and the keyboard again, and I just noticed the problem happening again.  Does anyone have any ideas of what it could be, or what I could try?

Answer : Laptop keyboard randomly types wrong characters.

I rebuilt the laptop and so far haven't experienced the problem anymore.