Bios problem. I own an averatec 4200 av4270-eh1 but it has problems recognizing the hard disk. I

Question

I own an averatec 4200 av4270-eh1 but it has problems recognizing the hard disk. I formatted it and it worked ok for a couple of hours but when I turned it off, I will have the same problem again. I was told I have problems with bios but I don´t know where to find a dos bios upgrade for my computer or what to do.my email is [e-mail]