Keyboard keeps typing letter o. Sometimes stops for a while, and then suddenly it starts again. I did scan it via norton 360 and I did clean the registry via ccleaner. Can u help me please.

You can use a USB external keyboard for temporary; test and fix your operating system using Norton Utility (download and run it):
http://download.cnet.com/Norton-Utilities/3000-18512_4-10907620.html
After finish (it needs some restart), please post the result (and the error message if any).

Start your PC and press F8 several times until the boot menu comes up. Then select "Safe Mode with Networking". Now get some or ALL of the FREE programs below..

Download, Install and Run Malwarebytes Anti-Malware:
http://majorgeeks.com/download.php?det=5756
When Installing choose the non-pro version.

Download, Unzip, Install and Run TDSSKiller:
http://majorgeeks.com/Kaspersky_TDSSKiller_d6895.html

Download, Install and Run Super Anti-Spyware:
http://majorgeeks.com/SUPERAntiSpyware_d5116.html

If you have an outdated Anti-virus program then Download, Install and Run Avira Anti-Virus:
http://majorgeeks.com/Avira_AntiVir_Personal_-_FREE_Antivirus_d955.html
Make sure to select ALL of the "threat categories" when you install or configure Avira...

You should be in pretty good shape if you run and install all of these programs.

I would suggest using a different antivirus protection program.

Several great tools to use are:

Anti-Virus - Avast , its free and very reliable.
Malware Protection - Malwarebytes, it too is free and a scan every so often keeps your computer bug free.
Unwanted Install Protection - Spybot Search and Destroy, again it is free and will clean your registry keys and keep your computer protected from hidden installers.

Avast: http://www.avast.com/index
Malwarebytes: http://www.malwarebytes.org/
Spybot S&D: http://fileforum.betanews.com/download/Spybot-Search-Destroy/1043809773/1

Please scan your computer again.It is due to virus

Sounds like the windows key is stuck down, pressing start+r opens run, start+e opens explorer etc. The start key being the one between control and alt.

sounds like one of the keys is sticking. check this out. If not uninstall driver and reinstall by plugging in again.

try to set on your MOUSE, here:

start-control-panel-mouse folder

hope this can help. :)

I assume you have a desktop system with a plug in keyboard; if you have a laptop please tell me and I will type up instructions on how to clean the keyboard on laptops.
You might want to try cleaning out the keyboard.
Unplug the keyboard and hold it upside down; shake it gently and allow debris to fall (pressing the keys can help).
I would also either use compressed air or a small computer vacuum on the keyboard.
Let’s see if this working…if not we might need a through cleaning.

Try the FN and num lk ey together the coloured blue then try typing again.