Programs designed for Windows 95/98 are far more complex than the old DOS programs. Their installation often requires putting system files in various directories. This means that you cannot "manually" install programs anymore (as you might have done with, for instance, WordPerfect 5.1), by creating a directory and copying all the files to it from a disk.  If you delete the program's folder to uninstall it, you have probably missed a large number of files which are in a system folder in the Windows directory. This also means that if you want to transfer a program to another computer, you can't simply copy the folder to a disk and put it on the new computer: you'll be missing vital components.
 

Most programs these days come on CD-ROM, and Windows 95/98 usually has "Autorun" enabled. Autorun means that as soon as you insert a CD-ROM, Windows checks it out and runs it. If it is an audio CD, Windows will run the CD Player; if it an installation disk, Windows will start the installation (or, often, a screen that offers choices, one of which is installation).

If the program is on a floppy disk, insert the disk, go to Start, Settings, Control Panel, and select Add/Remove Programs. Click "Install." Windows 95/98 will look for an installation file on the A: drive first. If it can't find the file, you may have to enter the name manually (usually, it is setup.exe or install.exe, but in very old or proprietary programs, the name could be different).

Most programs will ask you where they should be installed on the hard drive, and they suggest a directory. More complex (or more polite) programs may ask permission to create other directories, and a good program will ask before it overwrites any files (if you're not sure, answer "no" to that last one!).

The same Add/Remove Programs can also be used to uninstall programs. Find the program you want to uninstall in the list, click once to highlight it, then click Add/Remove. Programs created in last few years are smart enough to uninstall all (or most) of themselves.