When you say you can't get into BIOS, you've tried hammering F2 after pushing the power button and it still won't show up? Sometimes the window of opportunity passes so fast that you can't get in unless you're hitting the key over and over again as fast as possible.
Just to cover the bases, have you unplugged any internal wires or such lately? Had any jolts or unexpected shutdowns before this started?
Assuming none of the above is applicable, go download Ubuntu or Knoppix (or similar) and create a bootable disc (or flash drive). Boot from that. Then figure out if your primary drive is working at all. Access it, and backing up would probably be a good idea at this point.
If you can't access the drive, then you know that that's the problem, and you have my sympathies.
If you can access it, test it for errors. You may be able to fix it and then have it bootable. I hope someone else can give you advice on what to do if it's accessible, working properly, error-free, and still not booting.
If you can't boot from a live CD, then in your position I'd start running scientific method on components, starting by plugging the primary drive into another machine and seeing if it works. (After that I'd start button mashing, starting with F keys, so let's hope that if this is where your problem is then someone else in the community has a better answer.)
Facebook
Twitter
Instagram