The BIOS might be at least part of the problem. For example, if there was a problem with the CMOS battery on the motherboard (maybe the battery is dying) and the computer was off for an extended time (like when you were on vacation), the saved BIOS settings might have been lost. For that matter, BIOS settings have been known to just go away spontaneously (you turn the computer off and when you turn it back on, the saved BIOS settings are gone). When the BIOS settings are lost you'll usually be prompted to press something to go into the BIOS setup to fix things, so that could explain the "f2 for setup utility" prompt you mentioned in your first message. And the BIOS settings include the hard drive configuration, which could explain some of your other problems.
FWIW, if the clock in your system was still right, that would be a good indication that the BIOS settings had _not_ been lost, but it sounds like you haven't gotten far enough to see the time.
I don't think there is a BIOS "cache". There are saved settings (as I mentioned above) and in at least some systems you can clear the saved settings by putting a jumper on a particular spot on the motherboard. Where that is will depend on your motherboard, but I think that's mainly for situations where the settings are so screwed-up that the system won't boot up at all. If your system will boot, try to get into the BIOS setup and check the settings. This is normally done by pressing a key early in the boot process, before the OS (in this case Windows) starts to boot. The most common key is Delete, but it might be something else like F8. Since the message you posted mentioned F2, you might try that. If you can't find a key that works, you might also be able to get the computer's attention by holding down a key while it's booting, forcing a "keyboard error" that then gets you the prompt to press F2, or whatever, to load the setup utility.
If you can get into the BIOS setup utility and you think the settings may be wrong, or just aren't sure, there should be an option to load default settings. That would be a good place to start. Then select the first hard drive and see if there is an "auto" option that will try to pick settings based on the hard drive.
You also mentioned a keyboard error. What kind of keyboard are you using? If it's a USB keyboard then it may not be working, or working properly, if the BIOS setup is wrong. If it's a regular PS/2 keyboard (round connector that plugs into the back of the computer), then the BIOS settings aren't likely to be an issue.