|A 2628 is not a Thinkpad model, can you look around and find it? 2628 MAY be part or all of the type number.|
Sounds like you have a dead bios/cmos/backup battery
If you post "the numbers" for your Thinkpad, I can probably point you to the spot on the IBM support site where you can download the "hardware maintenance manual" and lean how to change it.
Is it dispaying an error number, and what exactly does the screen say?
Almost sounds like it's searching for a legitimat bootable device, as in, something wrong with the hard drive.
Did it work earlier, or did you just buy it?