Hi,
First, do a complete virus/malware scan to make sure that it's free from virus.
Here's a link with tools and tutorials you can use.
http://www.tomsguide.com/faq/id-1691891/removing-malware-proven-completely-remove-bitcoin-mining-malware.html
After doing a virus scan or cleanup and the same problem persist do try these troubleshooting steps that may help in resolving the issue.
- Check keyboard language settings.
- Open Control Panel and look for Region and Language.
- Check all tabs if they are all set to United States.
- If that doesn't work, try pressing those following keys which are not working using your onscreen keyboard (Ease of Access look for Onscreen keyboard)
- Connect an external keyboard and see if the same problem...