Samsung sp160GB reads as 120GB

Recommended by Wim's BIOS...

Recently I just changed my motherboard to the Gigabyte GA-MA78GM-S2H but now the bios reads my secondary hard drive as a 120gig and i cant seem to change it. I tried to manually set it in the bios but it doesn:t seem to let me. It also shows up in windows. but reads as unformatted. I have 230gb and 300gb usb drives plugged in working fine. Ive also tried plugging it in to a usb case and it doesnt read on other computers. Ive tried plugging it back into the original motherboard and that bios also reads it as a 120gig. Do I have to format it again? I have a lot of data i want to keep on it. If i have to format it. What procedure do i have to use so that I can recover as much data as possible.

thanks in advance