My Computer, right-click the drive, and select Properties. You'll want enough space to load the entire program, plus 10 percent of your drive's total space. If you don't have enough space, empty the Recycle Bin, look for files you can delete or archive, and uninstall applications you no longer use. Your options could include purchasing a larger hard drive. Either to replace the old drive or as a second drive in your computer.
Most computers can accommodate a second hard drive.
Check your owners manual. Not all components are compatible. Back up the Registry . Installation programs do all sorts of horrible things to user.dat and system.dat, the two huge and complex Registry files where Windows stores your configurations. For Windows 95, you can't back up the Registry with Explorer or with DOS's copy command, but there's a program buried on the Windows 95 CD-ROM that lets you do it.