Have tried different tpyes usb and standard plug type both have same results

Is this the same keyboard, or different keyboards you've tried? Just adapting the end to a different connection type is not an adequate test. Try a different keyboard or try the same keyboard on a different computer. If the problem doesn't happen with a different keyboard, then you need a new keyboard.

If you have the problem with a different keyboard, then we will need more information in order to better assist you. Please tell us about your computer. What operating system are you running? Make and model if it is a manufactured computer, otherwise the specs if it is a custom built one.

Also, make sure you have up to date anti-virus and anti-spyware. Also run scans with them. Plus, download HijackThis and post the log. Http://free.antivirus.com/hijackthis/

Try scanning your system for Malware/Spyware and viruses, they could be using keyloggers or just messing up the way your computer gets the key typing data.

Use:
- Spybot Search and Destroy
- Malwarebytes Anti-malware
- Hitman Pro
- Dr. Web Rescue CD (this is for viruses and it makes a CD you can boot to for easy virus removal)

If a clean up doesn't do it, repair your Operating System with your factory disc (no need to reinstall it completely, but you can do a repair which removes no data).

If that doesn't do it you may have some motherboard (hardware) related issues.