I sent my malfunctioning 500 GB SATA HDD to a shop, which reformatted it for me. I reinstalled it, and through my own stupidity, I changed which SATA ports it, and my old drives used. I have this returned 500 GB SATA, a 80 GB IDE with Windows on it, and a miscellaneous 160 GB SATA.
I reinstalled Windows on this returned drive, and have lost the ability to dual boot between it and the old Windows.
I was told by a friend that both drives with Windows had to be set to Master, not Slave. Is this correct? And how do I do this? My motherboard is a GA-P31-DS3L.
I'm not aware if SATA has the option of slave and master, but on the PATA there should be some pins that you can use to force the PATA to be a master. There is usually a sticker with a diagram explaining that. I've never mixed PATA and SATA, but I've dual booted with both of them and never had any issues with one PATA being master and the another slave. Then SATA seems to just... work.
Have you tried using GRUB? I prefer it to the Windows Bootloader. If you use Ubuntu it installs it for you.
http://www.gnu.org/software/grub/