Removing Windows 95

I would like to remove Windows 95 form a Packard Bell PB160 computer. The install file was removed by someone before I got the computer. I would like to install Windows 98SE. I do not have an upgrade program, I was given a new complete version and it will not allow me to install it over the OS ssytem. I do not have any of the original programs that were loaded onto this computer, therefore I hesitate to Wipe out the hard drive and start over.