Clearing MBR without destroying data

I just bought a new computer with SATA drive, and older IDE
cables on motherboard. I have two PATA/ide drives from my old
computer that are full of data, but also have a boot sector virus
on them. I want to keep the data, but remove the BSV. What is
the best way to do this? I was thinking I could attach just one
drive at a time (DETACH) the SATA drive, and run fdisk /mbr on
it. If I do that, will I lose all data on the drive?

If I reattach the SATA after that, then immediately run a norton
AV scan on the infected drives, would that then be safe? I need
to get the (cleaned and scanned) data off the old drives, then
completely nuke them and use them fresh. What is the best way
to proceed?