Help with BIOS

I have a dell latitude cpx. It is loaded with windows xp sp3. I can surf the internet ok but, my BIOS does not seem to work. My laptop fan is not working and my battery is not charging. When I try to go into BIOS to check things out it is not letting me navigate through the pages to check things out. I have been reading and am wondering how to update my BIOS. When I bought the laptop it came with a 10 g hardrive. I changed the hard drive to an 80 g hard drive and reloaded windows xp on it. So I am wondering if my BIOS is not compatible with this hardrive. the computer is very slow and seems to have a lot of heat coming from it. I do run a laptop cooler under it though as I do on all of my laptops. The hard drive I installed is a hitachi model number: HTS54108G9AT00

I ran a BIOS report:

BIOS ID: Dell Latitude CPx H500GT BIOS version: A14
OEM Sign-On: None
BIOS Date: 052802
BIOS Type: Phoenix
Chipset: Intel 440BXZX rev 3
Super I/O: SMC 958FR rev 1 found at port 3F0h
Motherboard Name: Dell Computer Corporation
Mother Model: Latitude CPx H500GT
O/S: WinXP SP3
BIOS ROM Socket: No
BIOS ROM Size: 512K
Memory Installed: 512MB
Memory Max: 512MB
CPU: Pentium III 500 MHz MAX: 600 MHz

Thanks in advance for any help or any helpful links

 

Seeing it's a P3, it may need a cr2032 battery. This holds the hard drive specs & passes them to Windows. When it's at near end-of-life, it can give the wrong time (being slow).
Use google & type in cr2032 battery. It's a small round battery, usually under $5 and a really cheap fix.

 

where is this battery? I have had the laptop all of the way apart for cleaning and never saw a battery in it.