Package all of the lots you create to files. The files will be located in the following folder in Windows XP:

C:\Documents and Settings\[user name]\[user name]'s Documents\EA Games\The Sims 2\PackagedLots\[your lot]

In other Windows operating systems, look for the "EA Games" folder in "My Documents". If you packaged a large number of lots, create a compressed folder. In Windows XP, right click a blank area in the folder of your choice, point to "New" and select "Compressed Folder". In other operating systems, or if you have a third party .ZIP utility such as Winzip, use a .ZIP utility. Put all of your packaged lots in the .ZIP compressed folder to save disk space. In the event that your computer must be reformatted or if your game data becomes corrupted, simply reinstall the game, then open the packaged files. Run them as you would any application or installation one at a time. You will probably need to decompress the files first. Consult your .ZIP utility for instructions.

If you do not want to bother compressing the files in .ZIP compressed files, try this. Package all of your lots to files (click the lot, then click the star next to the description, then select package to file). Your packaged lots will appear here in Windows XP:

C:\Documents and Settings\[user name]\[user name]'s Documents\EA Games\The Sims 2\PackagedLots\[your lot]

For other operating systems check the "My Documents" folder for "EA Games". Move the files to a safe location, such as a CD or another location other than your "EA Games" folder. If you ever need to restore you game or computer, do this, reinstall The Sims 2 and all expansions. Reinstall the lots one at a time (treat the files as install files, and do not manually install them).