Adding XP to 2000

I now use Win2000+SP4+RU1+etc. which I plan to keep for the foreseeable future. I wanted to add XP+SP2 (the SP pre-bundled on the original CD).

I tried making a new primary partition which the XP installer saw as F:. Win2000's boot partition was seen as C:. (D: and E: are data partitions.) XP was also added to the boot menu. But next time I went back to 2000, I discovered XP had trashed it. I got an error that C:\WINNT\system32\config\system was now missing. I ended up restoring the entire hard drive from backup.

I am willing to install XP into C: if that would help. But that way or another partition, can 2000 be protected from XP?

 

That is actually what I did. I have Acronis TrueImage Home, Disk Director, and OS Selector. While under a normal Win2000 boot, I shrank D: to make room and then made the new primary partition.