Windows 7 fields filling with repeated leters.

I have a
HP KZ854AV-ABA m9300t
4g Ram
300g HDD with@150g in use
Win 7 Home Premium 64-bit SP1
AMD Radeon HD 6450
64 bit

recently I am experiencing random (usually, however r n m) keys filling any fields I have available (Google search box, http address, amazon blanks, etc.) I ran Malwarebytes, system restore (2 weeks previous), I have no new hardware/programs, etc. It does this after an hour or so in use on any combination of programs, online or offline, games or whatever. It takes a system restart (most often) to stop the behavior. Any places where to look for this would be appreciated.

Try replacing the keyboard.

Or, if it is a wireless keyboard, replace the battery

If the 2 keyboard solutions above don't fix the problem; I'd suspect your Hard Drive or RAM sticks. That computer is going to be 10 yrs. old this year and is quite ancient. Hard Drives in PCs only last 3 years; 2 years in laptops. Chances are very high that if you've never replaced the hard drive in this computer since you bought it new, it's highly likely and can cause this type of problem. I'd suggest you test your hardware using the excellent and free TROUBLESHOOTING GUIDE I wrote from here: Windows 10 - Unclickable Task Bar

Best of luck,
<<<<BIGBEARJEDI>>>>