XP Pro reformatted, can't log in, can't run setup, says "keyboard failure"

My boyfriends mother gave me a dell computer that she messed up by triing to reformatt it. I can't for the life of me figure out the password, she told me what it was but it doesn't work. I tried to run setup from the dell loading screen but it says "keyboard failure" but the keyboard works just fine to guess at passwords. It says the same thing if I try to run the boot menu and boot the OS from disc. Would someone please help me, I really need to get this computer up and running and my hands are tied....thanks.

We can help you with a lot of things, but not passwords. TechSpot, as a matter of policy, does not get involved with password issues.
Tell us brand, model, and hardware configuration of your computer... including the Service Tag off the label on the back.

it is a dell optiplex gx260 product key WWBHB-2GJHR-BTPQ9-B96Y-WVPV8 I don't know what hardware configuration is...or the service tag unless it is this barcode with numbers and letters BM77T21 how can I get this fixed?

The fourth digit set is one letter short.

Send an email to TechnicianOnline@gmail.com and we will try to assist you there. We cannot help with passwords on TechSpot.

B9c6Y, the "c" doesn't work on this keyboard

Try reinstalling using a USB keyboard.