Solved BIOS Settings Will Not Save

Hi
I recently acquired a desktop PC with the following Specs:

O/S Windows XP Pro
System Model
AOpen KM400-8237
Desktop

Processor
2.00 gigahertz AMD Sempron
128 kilobyte primary memory cache
256 kilobyte secondary memory cache
Not hyper-threaded

768 Megabytes Usable Installed Memory

Main Circuit Board
Bus Clock: 166 megahertz
BIOS: Phoenix/Award Technologies, LTD 6.00 PG 09/07/2004

Maxtor 6Y080L0 Hard drive 80 GB

When I switched it on, I was presented with the two options of press F1 to Load default settings or Delete to enter Setup.

I enter Delete to reset the BIOS settings and reset the date and time and the required boot up settings.
After I unplugged the PC and switched it back on again the settings were lost and as the pc had not been used for a good, long while I suspected that the CMOS battery was dead.

I bought another one after opening the case and removing the old one and checking the serial number, from eBay (I know) only to read after the purchase that someone had written that a battery bought from them was a dead one, so I bought another from a reputable dealer.

The battery slots into a vertical slot on the motherboard and a metal clip was over the top of it, not touching it, looked as if it was only there to save it falling out if the case was bumped, moved etc

After replacing the battery and ensuring that the battery is well bedded in and touching both the sides of its slot, using the good one the BIOS settings still would not remain as set, so I used the suspect iffy one from eBay still no joy.

I have double-checked that everything was connected and bedded down correctly, but still it will not save the BIOS Settings if unplugged from the mains.

Can anyone assist or point me in the right direction on how to fix this problem?

Many Thanks In Advance

Toby963