i think he may have wanted to know a bit more than that...
like ahajv4life said, backup your microsoft office, if you dont have the disk for it anymore then im not sure what you should do...i cant help you on that one. now onto the reinstalling.
i dont recall Windows 98 supporting the boot from cd feature, at least no disk ive worked with has...so youll need a startup disk....first get a floppy disk..umm not sure if you can do it in 95 but try it anyway...put the floppy in, go to My Computer, right click on 3 1/2 floppy, click format and then check the box that says "create startup disk" and format it...but im not sure you can do that on Win 95...lemme think for a second..ok you can either start your computer in MS-DOS mode, or open the command prompt by clicking Start>Run>Command..then with the floppy in the drive type
"format a: /sys" without the quotes, that should make a start up disk...
now...go into your computers BIOS, usually by pushing a certain key when the PC first boots up, such as F1,F2, Del...something along those lines, you may see a message that tells you which key to press, or you may have to just hit buttons randomly..but when you do get in there you need to find your boot order...sometimes its under "boot" sometimes its lord knows where...but once you do find it, set it to boot from the A: drive first...save, restart the computer with the startup disk you just made in the drive..it should start up MS-DOS, if it give you an option to start with or without CD-ROM support choose WITH...once it takes you to a command prompt that looks something like this "A:>" with a blinking cursor after it..with the Windows 98 cd in the drive type D:setup, sometimes its E: setup...then it should start the installation process, part of which is reformatting your hard drive, but all that stuff is on the cd and the instructions are all right there. i hope i didnt type all this for nothing
