When using the Windows operating system (such as Windows 95 and Windows 98) you can uninstall software by going into the "Add/Remove Programs" Control Panel available from the START MENU:
START >> SETTINGS >> CONTROL PANEL
Once you've opened Control Panel look for the "Add/Remove Programs" item. Double-click on it, then look for the item you'd like to remove (such as "QuickTime", for instance, if you want to remove that browser plug-in).
Select it, then click on the "Add/Remove" button -- Windows will then try to automatically uninstall this software. IF YOU HAVE DIFFICULTY removing a software product, or can't find it under the Control Panel, consult the installation documentation for that product (install documentation typically includes a discussion on how to remove or uninstall as well).
After uninstalling software (or a collection of software programs) it's a good idea to restart your computer before doing further work.