When I first built my rig, I partitioned my 1TB Hard drive into 4 partitions. On the first one I installed XP 32-bit, on the second one I installed XP 64-bit, on the third one I installed Windows 7 RC1 64-bit, and the fourth partition was a storage one.
Later, I got a 750GB HD and I deleted the 4th storage partition from the 1TB HD.
Today, I wanted to install RTM since I have a legit key. So, I went ahead and uninstalled the 7 bootloader using EasyBCD. This reverted me to XP 32 and XP 64 prompts when booting. Then, I installed 7 RTM on the same partition RC was on and then the XP entries disappeared.
I would like to add XP 32 and XP 64 to the boot manager. I tried what people have suggested here with no luck. When I choose XP in the boot options, I get an error saying that the boot.ini file is missing and the NTDETECT failed.
I tried adding XP in EasyBCD and the drive it was always pointing to was F: (which is another physical drive I have)
So, I went ahead and copied boot.ini, config.sys, msdos.sys, NTDETECT, and ntldr to F. After that, I get the prompt under windows 7 when booting, but if I select XP 32, I get an error saying windows could no start because ntoskrnl.exe is missing.