L420 gets stuck at splash screen or steady beeping.

[455olds]

I have a L420 that gets stuck at the thinkpad logo when booting. It is inconsistent,sometimes it boots ok and doesn't get stuck or other times it will do a steady beep for 30+ seconds and then boot.
It seams unlikely that a key is stuck. This computer is in like new condition and nothing has been spilled on it. The problem happened after I let computer sit for a couple years.

I tried upgrading to windows 10 but I didn't do full clean install. I also tried western digital hdd diagnostic from ubcd. I am running memtest now but no errors.
I wanted to try a bios update but I can't get utility to work. I cant find a way to manual install. Lenovo solution center does not show a bios update after running "system update" I am running bios version 1.16

This is the bios utility I tried to use. http://support.lenovo.com/us/en/downloads/migr-77079#os
Maybe i need to revert back to windows 7 to use this utility?

[455olds]

I restored back to windows 7 and was able to get bios update utility to work. After bios update I did a fresh install of windows 10 64 bit. (I had windows 7 32 bit) It seams ok so far. I think bios may have been corrupt. Not sure why it would do that after sitting. It was fine before I stored it.

[rkawakami]

Could be a case of "bit rot". Flash and EEPROM memory, even though they are supposed to be non-volatile, can sometimes flip states over time.

[455olds]

Pretty confident i have it fixed. I spent all night on it and posting from it now,no problems.