Delete the folder holding Windows 98 (by default, C:\Windows). Then, edit
the boot.ini filed in Notepad to remove the entry for Windows 98. Boot.ini
is a hidden, read-only folder, so you need to set your system to view system
files and to show hidden folders, then remove the Read-Only attribute for
the file.
Save your files. Full format the system and now installed the window which ever u like to have. There is no othe way. In future don't use new installation instead use upgrade
Rg.