I'm pulling my hair out on this one...
Compaq Presario R3000- yeah, I know it's ancient but it's a specialized piece for a sewing business (handles blueprints and links to sewing machine)
The old battery only lasts about 30 minutes. I ordered a new one 'direct part replacement'. It's a genuine Compaq battery. I put the new battery in and it was recognized, but wouldn't charge. The power meter showed a red X over the battery symbol. I tried every suggestion I could find to no avail. I was going to do a BIOS upgrade but the file I got from Compaq for the R3000 showed that it wasn't compatible, so I didn't want to chance bricking the laptop. Sent the battery back and was given a replacement from the vendor.
This time I followed the procedures by the book. No battery installed, unplugged the AC, and bled out the power (held power button down for 1 minute). Then installed the battery and plugged in the AC. Let it set over the weekend. Nothing new- same issues with the previous battery. I also tried uninstalling the battery from Device Manager, but that does nothing.
The only thing I haven't tried is resetting the CMOS, not sure if that would help but would require a complete teardown.