Locking/unlocking windows 7 forces me to restart computer (return pressed)?

Hello,

I'm having problems with windows 7. When I lock windows (WIN+L) and unlocking them back by entering password it's like something is pressing return all the time.

For example if I open chrome and type in google, only 1 letter can be typed then it's instant searching of that letter like 100 times a second (resulting I have to prove I'm not a robot after I reboot computer).

Sometimes it's just best to lock screen instead of signing out or shutting down. I really can't find solution to that.

Any help would be much appreciated.