Since this post is one of the first I got when googling similar problem, I've decided to update the issue. I'm having this kind of problem on Inspiron m5110, user said that keyboard has stopped working, touchpad worked, but as of now, when I have this notebook, touchpad doesn't work either. It's not a windows problem, and it's not a hardware problem. Keyboard works in bios, and also works on errors (the adapter is 65w instead of 90w and I get an error for that, f1 works there),but right after it tries to boot into something keyboard and mouse stop working. External keyboard and mouse don't work during windows 7 boot or reinstallation, but that's because of the USB3 driver I guess, since they work in installation of Windows 10. Right now I have windows 10 installed, external mouse works, keyboard doesn't. In device manager it shows PS2 keyboard and Dell touchpad are present, but they don't work. Bios seems to be the latest, so I'm kind of out of options atm. I haven't tries short circuiting the bios...