I want to remove windows 7 build which is not genuine from mu P.C.

lol "by mistake". As if your firewall and security updates have anything to do with Windows.

Anywho, go purchase yourself a nice legal copy of Win7, reformat, and then load the new OS.

If you purchase the same version that you currently have then you do not have to reinstall. Start, rt click on Computer, select "properties" and then towards the bottom select "change product key" and then enter in your product key (this is what I had to do on my last reinstall as I lost my win7 disc, but still have the key on the case.

Sounds like you have an illegal copy of Windows and one of the security updates that checks for these copies has flagged your OS as pirated --- you will need to contact Microsoft to purchase a valid product key or purchase a valid copy of Windows and install it.

Since you can not be sure if the Pirated OS that you have on the ssystem included any other Malware or Tracking Software the best Option would be to buy a valid copy of the OS and completely format your HDD and start from scratch - installing the valid copy of windows and than reinstalling any programs - Otherwise if you just purchase a valid License and keep the current install any Malware that might have been included with the pirated version could still be present so be careful if ever using any personal info on the system (Banking info, passwords, credit card numbers,etc.,etc.) as you never know if the pirated version also had tracking software included and the system may not be secure unless you wipe out the entire thing and start over with a valid copy.

We need a hall of fame for most entertaining quotes.