Keys on keyboard not working windows 7 vaio

Sony VAIO laptop VPCEA4S1E running Windows Home Premium (64bits).Since a couple of days I have a strange keyboard problem: some keys ( p, Backspace, F F F F F FF12) are not working as expected.Hi I have sony vaio notebook and the keyboard is not working properly. I cant type letters of numbers and even the back space is not working. Some of the keys on my laptop (Sony Vaio VGNFSF810W) stopped functioning. So I bought a replacement keyboard from Sony and installed but the problem remains.

External devices do not work (however the keyboards function keys work, along with the sony vaios assist/web/vaio buttons). The touchpad is set to on vai the function key + F1.

Sony VAIO - Keyboard is not working correctly

I have a Sony Vaio SVE11116FGW, Windows 64-bit. I had installed Windows but I returned to Win 7. I have also another problem - whenever I start the computer, it asks me to choose the operating system. When the keys on the keyboard are not working properly, it is important to make sure that the keyboard is cleaned properly. Using a can of compressed air could be used to free up any dust that may be preventing the key to work. Well I was typing on my laptop which is a Sony Vaio VGN-N320E and the acted as if they were stuck.

Then I restarted my laptop only to come across a continuous beeping sound at the start-up screen, and when it finally rebooted I got to where I type in my password but the keyboard is no longer working.