Update of BIOS - need your help re problems

Having recently updated my BIOS (background reasons given below for those interested)  I now find I have a whole range of problems that were not previously evident:

 

1. The BIOS initially flip-flopped on successive boot ups between recognising 512MB and 256MB of RAM but is now stuck at 256MB (I have 512MB installed) and the machine is painfully slow.

 

2. The fan is noticably more active.

 

3. I've received a couple of high temperature warnings (vents are free of visible dust).

 

4. The battery status light is now off even when the battery is fully charged and I'm running on AC power.

 

I'd be very grateful to anyone who could shed any light on why I'm experiencing these problems.

 

Further background info for those interested

 

I've had my 5150 since August 2003 and had very little trouble until a week ago when after hibernation the machine would not reboot and I was unable to boot from a CD or floppy.

 

By installing the hard disk in another laptop I was able to run check disk which corrected one or more bad sectors. On reinstalling the hard disk the computer booted up fine but I wanted change the BIOS settings to make sure that the CD (optical drive) was addressed first but couldn't because pressing F2 did not interrupt the boot up sequence. The Windows based BIOS updates would not run so I installed version A23 from CD but I had to remove the hard drive to force the CD to be read. Immediately after intalation a problem with a change in memory was reported.

 

With version A23 installed and the hard disk replaced I was able to run the Windows A38 update but the memory problems have persisted. By experimenting with the position and number of memory cards it looks as though the problem lies with the slot A hardware not the cards themselves.