While several questions have already been answered about removing an OS from a dual-booting machine, most refer to Windows 7 vs. Linux/Vista/XP. I have W2K installed on my older HDD (Drive C). Later on I bought a new HDD and installed XP's under W2K environment. Each time I turned my PC on, I had the choice of W2K or XP OS, which I still have. I eventually stopped using the w2k OS and as the older HDD where this OS is installed is getting old, I plan to remove it completely. The problem is that the active master boot record is on this very HDD. So when I remove the HDD, I get no OS loader, no matter what boot drive I choose in BIOS. Apparently I have to set the boot record on the newer HDD with XP's. Some advise to use the bootable XP CD and try to set the active MBR from there.. I don't have the CD anymore. Regardless, I suspect there is much less to solving this problem than running the recovery console, like a simple boot.ini file edit. But I might be wrong.