Why my pc is booting with empty registry?

Hello,
I am using Windows XP and currently, my PC is booting with empty registry. A week ago I removed few old unused programs via Add/Remove programs. But I noticed Windows XP didn't remove the registry information and when I went to msconfig.exe to check some startup options, I found a bunch of startup items that were simply blank lines. I want to get rid of them. Please someone tell me, step by step, how to safely remove blank entries from msconfig and registry.
Thanks.
