BIOS rom checksum - after replacing the battery

[uga]

Hello there.
I replaced the motherboard battery since the system clock was giving me the wrong date/hour every time I started the PC.

The problem is that, immediately after the battery replacement, I received the following error:

"Bios Rom Checksum Error
Detecting Floppy Drive A media...
Drive A Error. System HALT"

I cannot enter the operating system or the BIOS.
During the above error my PC is continually making and alternate beeping sound.

I checked the new battery (CT2032 3v) with a digital multimeter to see if the battery had enough charge, and the battery is ok, so that is not the problem.

Could it be that after replacing the battery the CMOS was wiped out and therefore the checksums between the CMOS ROM and Bios are different. (I don't know the technicalities so maybe I'm just saying stupid things as I'm not sure on how all this system works)

Anyway I tried resetting the CMOS, but the problem persists.

I have never had problems with the PC. The PC worked fine with the old battery (well...except the system clock).
Just out of curiosity I tried to put back the depleted battery (the one used when the PC was working fine), and the problem persists (obviously).

I would like to hear your thoughts on the matter before trying to flash the BIOS (I never did it in these conditions, and I'm not 100% sure of the correct procedures...not mentioning the fact that I would have to find a floppy drive since I don't have one in the machine).

P.S. I always use an anti-static bracelet for every operation inside the PC, I turn off the power supply unit with it's switch and I physically unplug the power cord from the electrical socket.

Thanks.

EDIT: Is the "BIOS TBL" jumper useful in these situations?

The PC:

Foxconn Winfast NF4UK8AA-8EKRS (nforce 4 ultra chipset)

AMD64 3000+ socket 939 CPU
2GB (4x512MB) RAM PC400
Geforce 6600GT with 128MB
120GB IDE HD + 80GB IDE HD

 

[uga]

Well. I sorted it out.
I removed all the hard disks/dvd-rom and kept only one dimm of ram (512mb) and the computer changed the beeping sound.
I then decided to replace the RAM with another stick and the system run fine.
I then tried to put all the ram back (even the one that gave me beeps) and everything is ok (so it seams that no sticks of ram are defective).

So now everything is functional and back as before (with just 2 sticks of RAM switched).

If I remember correctly, in he past I changed the timings of the ram, and probably after I replaced the motherboard battery something was expecting some values for the ram that where evidently changed.

Now I have the default ram timings.