I bought the laptop almost a year ago and it was working perfectly, but then a it got a virus from downloading something from the internet. The keyboard stopped working but I managed to install a new version of windows 7 Ultimate, but the keyboard still won't work, i downloaded and installed all the drivers I found but still it wont work. And when I got to devices and printers, the is a yellow triangle at the laptop's icon and needs says needs trouble shooting, but when I troubleshoot it fails to install the drivers. One of them is called 'Base system device'. Everything else is working except the keyboard, I'm using an external USB keyboard right know, but its very uncomfortable to use. Please help!