Win98SE won’t boot after HD replacement

Hi there…I just replaced my desktop’s HD, and when I tried to boot up, I got nothing but a blank screen and a constant “beep…beep…beep”, with the HD light staying on. Swapped back the old drive and got the same thing. Now, granted my box is only about 6 years old (since last mobo & CPU upgrade), and it did work (got the “bad sectors, do Scandisk” screen quite a bit, though), but I thought it would at least work again once I put the old drive back in. Any idea what to do (other than listen to my landlady and break down and buy a new box)?