-The Windows 95 installation procedure is pretty easy to follow, however you should always be prepared for the "worst case scenario." It is recommended that you perform a full backup of your system prior to installing any new operating system, so that recovery, in case of disaster, is expedited. This "good practice" is not specific to Windows 95 installation. To safeguard your computer and its data, regular backups should be performed. See Backups
-At a minimum, you should backup all of your critical system configuration files including:
CONFIG.SYS
AUTOEXEC.BAT
WIN.INI
SYSTEM.INI
PROGMAN.INI
WINFILE.INI
*.GRP files
-It is also a good idea to have your original installation disks for DOS and Windows 3.x for the "worst case" scenario recovery.
-The Windows 95 installation routine will also give you the option of backing up your Windows 3.1 and DOS files to another directory on your disk, in case you want to uninstall Windows 95.