Hello. I have a Dell Vostro 2520 Laptop. One day the keyboad and touchpad suddenly stopped working. Then suddenly it starts working again. I reformatted the drive and reinstalled Windows 8.1 However, even in the BIOS it was not working correctly so I knew that this was NOT a software error. I still installed Win 8.1 and all the drivers. It didn't work. Now thinking that the hardware must be damaged, I used an external keyboard and mouse from my desktop PC (which had previously worked with this same laptop) but to my surprise even that was NOT working and giving the same problems! Like sometimes it works, sometimes it doesn't. If I press certain keys, like Win key or click then it stops working, when I click all the function (F1, F2, etc) keys then sometimes it starts working again, but only for a few seconds. Thinking that this is NOT a software problem NOR a hardware problem, I updated the BIOS, but the problem still persists! Its NOT the OS, Driver, BIOS, Hardware problem since I changed ALL OF THAT! So what is this?! Thanks in advance for your help!