Forgot bios password

So I purchased my desktop some 5 yrs ago and at some point lost interest in the business I had so I shelved the computer. Then a friend of mine needed a hard drive for a computer he had and I had several computers in my room and when he asked me I didn't think of it and I told him that he could get whatever one he wanted well he took the one out of this computer my optiplex and so I go to go to set up the computer use it and there's no hard drive so I install another hard drive thinking no big deal and guess what there's a FiOS password needed for it to even set up and I don't remember what it what it is so what do I do