So you want to install windows 95?
To format, put your windows dsk in your Optical drive, and make sure in the BIOS that the CD drive is set to boot first.
A message will appear saying press any key to boot from CD.
So, follow the instrauctions, and once the HDD is formatted, it will insall the OS.
These isntructions are the same for any MS OS, so if you can get a windows 98 disk, then you can re install that.