Thank you so much for the help， 燕趙悲歌. I made it with other

Thank you so much for the help， 燕趙悲歌.

Eventually, I made it.

Actually, the problem is that I am not allowed to format C drive unless there is no installed XP system DETECTED on C when booting the computer.

Here, I am sharing with you what I did. Under 2nd XP system (on D drive), I deleted not All, but most of the system files. And then, reboot the computer with CDROM, which is new XP disk at this time. Since no operating system has been detected this time by the computer. I was allowed to delete both partition C and D. After formating C drive, the new XP system can be installed. I learned a new lesson. Thank you very much, again,燕趙悲歌！