Thinkpad T20 and the infinite spyral...

Hallo all! (first post here) - I hope this is the right place for this... ok let me tell you the incredible problem i am experienceing on my t20 :
I have a t20 (bought it on ebay + a "new" battery which lasted 1:15 hrs.) which was running nicely until today. The only deal was that i could not stand the miserable 1.1/4 hour long battery (thought it should last at least 2 hrs or so) so i started tuning up the battery settings with the Maximiser app etc. until i came into the ibm website and found out that my bios was version 1.21 and that the latest one (1.22) provided a "better power management". So what would you do? of course, i downloaded the non-diskette version of the bios (i have no floppy reader!) and started the upgrade. All went fine - the machine halted afterwards (as described on the manual) and then i rebooted the laptop. Tadah! Now the laptop doesn't seem to recognize the battery and gives me strange behaviors, includind that the battery does not recharge. (actually, the battery led goes to still orange, which should mean it is charging, but after some hours the battery is still cold plus if i detach the ac adaptor, the laptop turns off in a couple of minutes) Additionally, when i unplug the ac, the battery maximiser doesn't seem to understand it's running on battery, and the plug icon in the systray remains there (instead of turning into the battery one).
So what i figured out, is "I absolutely need to downgrade the bios!" but guess what : the program claims a fully charged battery to avoid sudden and dangerous poweroffs! so... WHAT CAN I DO!??!?!!? this is a nightmare, i can't stop having problems with my thinkpad! help me please!!!