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:. I made the partition using Disk Director during a normal Win2000 boot. Win2000's boot partition was seen as C: after booting the XP CD. (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. Can 2000 be protected from the XP installer?