laptop battery not detected

I have a Dell Inspiron 1300 laptop. A couple days ago, it became infected with the "Cyber Command of California" virus. I eliminated the virus by first doing a system-restore to a restore point a couple days earlier, and then running Malwarebytes to quarantine and remove. Now, it may be entirely coincidental, but since about that time, my BIOS is not detecting the laptop battery, and the "battery power" indicator light on the front of the laptop flashes orange. If I leave it on battery power, it will shut down. Maybe it is the battery, but it seems to have happened all of a sudden, with no prior deterioration of the battery life.

Also kind of confusing, if I leave the battery in the laptop, and unplug the power adaptor, the machine will stay powered up - at least long enough for me to move it to another location and reconnect a power adaptor. So it must be getting SOME power from the battery, even though it does not "detect" the battery. I unplug the power adaptor without the battery installed, it will, of course, shut down.

I have read some sources that have said similar problems might be fixed with a BIOS flash, and I'm wondering if the system-restore might have had anything to do with that. I also have some reservations about doing a BIOS flash - and I'm not quite sure the best way to go about it.

This machine has a new, non-Dell HDD installed, but it met all the requirements (SETA or whatever), and has been functioning fine for several months... Does having a new HDD in any way affect the BIOS? If I do a BIOS flash, is it going to be expecting the original equipment HDD?

I can get a new battery under warranty - the current battery is less than 2 years old. But I'm concerned that if the problem is NOT the battery, and it doesn't come fully charged, and if the machine still does not recognize it, and/or fails to recharge it, then I will not be able to do that relocation described above without the laptop shutting down - as I can still do now with the old battery (although if it is draining, that may not last long.)

I've also read the failure to detect / or recharge the old battery could be due to a faulty power adaptor. I have two adaptors, and this problem occurs with both of them, and it had never occurred with either one before, so I doubt if the adaptor is the problem.

I've also read it could be the motherboard. I do recall that, even before I got the current battery, the "battery power" indicator light would flicker between green and orange - but the batteries always seemed to recharge fully.

So. Any ideas? And if this isn't the best forum for this topic, any suggestions?