Make a Winxp repair install recognize the previous installation.

In the past (too long ago) I remember going through this before but can’t remember the steps or even if I was successful but does anybody out there know any steps I can take to make a Winxp repair install recognize the previous installation when it won’t? I’ve tried bootcfg /add rebuild,fixmbr,etc. but am at a loss. I’d appreciate any input on this subject. -Kelly