When Im using ctrl+c, ctrl+a, ctrl+x are working but ctrl+v is not working. What I observed in browsers when I'm using facebook, hangout screenshots are sent when pressing ctrl+v. In notepad, office applications there is no action when using ctrl+v 

Kindly go through the following KB article:

Cannot Drag or Copy and Paste File

If possible you may try with another keyboard to check the issue.

Hi,

From your state, I infer the most problem for the issue is system files damaged.

Firstly, you can start the Windows in clean boot mode to check whether it works. If the problem solved, I guess it may exist the conflicting software.

https://support.microsoft.com/en-us/kb/331796

You can determine which one can be the cause by using dichotomy in MSconfig. Checking on half of Non-Microsoft service and restart, determining which half of the services cause the issue and repeating to check half of the problematic half services.

If the problem doesnt solved, scan the virus in safe mode due to the virus may block the module of anti-virus software. Then run SFC tool to repair system files.

https://support.microsoft.com/en-us/kb/929833

In addition to that, we have found an article about the issue which is similar to yours. You can try the steps in the link below.

https://support.microsoft.com/en-us/kb/309662

Wish you will troubleshoot the issue smoothly.

Best Regards

Simon