Hello everyone, I've had an NEC Versa 6000H for a while, but it's until I recently decided to take it apart to pull out the old Ni-MH battery and replace the CMOS coin cell. It initially seems to work out, but after a few boots now I can no longer make the laptop POST for some reason. All it does is producing a sequence of 1-2-2-3 short beeps and then halting there without the screen even turning on. I tried reinstallling the Ni-MH battery to no avail. I was doubtful if the BIOS is corrupted somehow, but I have no way to make sure of it. The service manual suggests upgrading BIOS with a floppy, which I also tried, but it doesn't seems to do anything either.

Thanks so much for everyone's help.