The last time I bought a computer it came as a package which included printer, scanner, tower, monitor, mouse, keyboard and speakers. I purchased this online and the brand name was IBM. I am ready to replace my setup and cannot find a place that sells the same package. All I can find that is close is one that sells the tower, monitor, keyboard and mouse and speakers. Not printer or scanner. My question is: will I have to buy these items separately or can I use my old ones with the new setup? They were installed using Windows 98 and my new setup will either be Windows XP or Vista.

You can use your old ones, but if they came with a Windows 98 computer, chances are they are old and low quality. You would be better off getting new ones- they would be much better, and now you may have more opions. For example, for your printer, why not get a laser printer or a printer/scanner/fax/copier? You can get a microphone with your speakers. Your old mouse is probably trackball. You would be amazed in how much better a wireless laser mouse would be. If you do decide to get new stuff, look around BestBuy and you are likely to find what you want and some stuff you never expected. Also consider new stuff, such as a webcam.

Most likely you will need to purchase new equipment. If you bought the computer with Windows 98 then most likely the printer and scanner will use parallel cables and not usb. You're not going to find a new computer that has a parallel port. The scanner might have it's own card but with something that old you're not going to find an XP/Vista driver for it. Dell, Gateway and a lot of the online places will sell you those things when you're building your computer so you can be sure they all work together.
BTW... if you have the option I don't recommend Vista. The hardware requirements to make it run the same speed as XP are a lot higher. It's a nice looking OS but it pretty much ends there.