Help pls. Bios error or another issue?

I am having an issue with my computer and hoping someone can help. I have an HP Pavilion a420n. It was running fine when I shut it down for the night. Powered it up next morning and had a screen come up that stated bios in this system are not fully ACPI compliant. Cant do any kind of restore because I cant load anything past this screen. I had not downloaded or changed anything before this happened.
I did purchase this computer used but it had been running great until this happened.
Hope I can explain this and make sense...Hubby took the HD out and put it into another computer we had and it wouldnt work(fit but wouldnt run). Also we took the hard drive out of the working computer and put it into the one we had the bios error on and still wouldnt run.
I am stumped..I understand if the HD in the HP went bad why it wouldnt work in another computer but cant understand why the HD from the working CPU didnt work in the HP...
Does anyone have any suggestions...well other than drop kick it out the front door LOL.
Thanks in advance..

Melody

 

Windows will only run on the machine it was installed on. So when you switch HD without reinstalling Windows then Windows doesn't like it and does not want to run in the different machine.

In your HP with the BIOS problem try putting the original HD back in unplugging the PC and taking out the coin shaped battery for a minute or two then putting it back in to reset the BIOS to defaults. See if there is any change in the start up message.