>Are there any tool that comes with Windows that will make backup of the registry?

Scanreg is a commandline utility with backup and restore. Also win98 does an automatic backup to windir\sysbckup dir. Also you can use export function of regedit.
In most cases scanreg didn't work for me and I needed to manually extract cab files in sysbckup. If nothing works overwriting system.dat with \system.1st sometimes help (of course it 'forgets' after first time reg changes but at least you can startup).
Also you could use system tools\Backup to create a Emergency Repair Disk with registry info (under w2K exists but as I remember in win9x too at least as a command line option ERD ?).
Cetin