Please post some system specs eg. CPU, Motherboard, model of keyboard/mouse/controller would also help in this case, it helps in narrowing down the issue. This does sound like an issue some LGA 1156 Asus motherboards had where the system could get unstable if a key was held down too long, Asus did eventually release a BIOS update to resolve that issue, but it could be related to something else. Seeing as updating the BIOS is a somewhat risky procedure that can brick a motherboard if done incorrectly, I wouldn't recommend doing it unless you know for sure that a BIOS update will fix the problem.