I've spent lots of time trying to solve a similar issue on Lenovo x201i, and eventually I did, but I don't know what helped exactly in the end. I used to get "gt" when I typed "t" etc. When I connected external keyboard, it worked, but I need the built in keyboard to work
The last thing I did before it started working was downloading this tool from Lenovo website:
http
/support.lenovo.com/us/en/products/laptops-and-netbooks/thinkpad-x-series-laptops/thinkpad-x201/downloads/DS102384 and running it. It configures some "enhanced keyboard". Even though I don't have any "enhanced" keyboard, I have a ususal one, after running through all steps in the tool, the keyboard started working as expected
Other things I did but they didn't help (or maybe a combination of them did help in the end):
1. Removed keyboard through "Device manager", added it again.
2. Removed all input languages (I had 6, left only English).
3. Update antivirus (avast), checked the whole system, no viruses found
4. Downloaded "Microsoft Security Scanner", checked the system with it, no viruses found
5. Changed windows location, language settings to english
6. Tried updating the system (Windows 8), which I couldn't do because some permissions in the system are screwed up
7. Turning on/off numlock/scroll lock (didn't help)