Updated my BIOS today. Lenovo Thinkcentre A61. When booting, it mentioned a CMOS error. I reset CMOS by shorting the jumper. Now I can't remember what the correct position of the jumper is, the labelling isn't clear. I've tried booting the PC with the jumper in every conceivable position and get no response - just the fans spin up.
Can boot without the jumper in place.
i've taken out the BIOS battery and am about the replace it to see if that makes a difference.