xp install

I did a clean install on my dimension 4100 (from ME to XP home). I deleted the hard drive and changed the file system to ntfs. Everything seemed to go great until I turned on my pc this morning and got a black screen asking to boot from the a drive.!! ouch. I booted with the Me startup floppy I had,from there got the boot to cd and did a repair reinstall just to get back to what looks like normal. Can anyone help. I'm afraid to shut down now!