like you find with other brands. You should have an operating system CD, a resource CD with the drivers required for the hardware installed and programs CDs for the factory installed software. You also need the product key numbers. Do you have all of this? If not, don't start a reinstall until you do.
You can download, install and run Belarc to find what is installed on your computer with the product key numbers. If you don't have the drivers, you can go to Dell's web site and download what you need.
You can also do a repair rather than a reinstall. Do you run regular scans for spyware? How about virus scans? What type of maintenance do you perform regularly. While reinstalling everything isn't real difficult, it does take time and preparation. If you don't, you can have a mess.
I have a Dell 8200 which came with Win ME. I changed to Win XP when it came out. It's running really slowly so I would like to reformat and start out as new. Will the Dell Restore CD work since I changed to Win XP after I got the disk?