Space key gone wild... sets randomly spaces when texting

I am working at a desktop pc with Win 8.1 installed. When typing, spaces appear randomly (also in the middle of a word - it is not as if the space key had got stuck). Nevertheless I got a new keyboard but the same problem occurs. I removed the keyboard driver - did not help. The keyboard is not wireless, plain USB. Seems though, as if the fault appears only in programs of the MS office suite. I would be grateful for any advice.
Rembert

Did you try changing "Repeat Rate" and "Repeat Delay" in Control Panel > Keyboard Properties ?

Hi Count,
thank you for looking into my topic. Your suggestion does not seem to help, as the spaces occur without the spacebar actually beeing touched at all.
Thanks a lot,
Rembert

Try using a different font - many programs will auto-space your words/letters in an effort to format the text.