Running dual boot on 5110N (AMD powered, A8, 4G RAM), Linux Mint and Win7 Professional. Some time ago built-in keyboard stopped working so I plugged in USB keyboard. But with that one I couldn't change my OS in GRUB. Than I noticed that from time to time built-in keyboard works. So, when built-in one works, USB one also can change options in GRUB. When built-in doesn't work, USB one doesn't work in GRUB either. Works pre-GRUB menu, works after, works in OS, but doesn't work in GRUB, can't change options.
Today, after the restart, laptop got stuck in GRUB. there's no 10 seconds countdown to select OS. Tried restarting it several times, tried, opened it, took out BIOS battery for couple of seconds... Noting. Still stuck in there.
I'd appreciate any constructive solution. Thanks in advance.