Here's my problem: the "L" key stopped working on my keyboard. So I switched out for another keyboard. On THAT keyboard several number keys (not the keypad) are not working. (5 and 6 are). Both keyboards work fine on other computers. On Screen Keyboard all keys work fine. The same keys do not work in the BIOS setup either. I've checked for viruses and malware. All clean. I've uninstalled and reinstalled drivers. I've switched the keyboard to another USB port. So now I'm stumped. Suggestions?