1. Assuming your system is still functional enough to let you do so, back up everything you can find (documents, photos, graphics, saved e-mails, updates, drivers, and so on; don’t worry about software programs because you’ll have to reinstall those, anyway) and close all applications.

2. Choose Start➪Control Panel➪System and Maintenance➪Administrative Tools.

3. In the Administrative Tools window, double-click the Computer Management link.

4. In the resulting Computer Management window, click the Disk Management link on the left. In the resulting window, right-click the drive or partition that you want to reformat, and then choose Format from the shortcut menu that appears.

5. In the resulting dialog box, select the options you want (file system and size) and then click OK.

The two file systems types that you can choose from are NTFS and FAT32. NTFS, which stands for NT File System, is the default. This format supports long filenames, and various storage, security, and recovery features of Windows NT. FAT32 is an older system used by the now antiquated MS-DOS to organize files. You are probably better off leaving NTFS as your file system choice.

Note that you have to be logged on as the head honcho — the system administrator — to perform these steps. And it’s worth repeating: Reformatting a drive wipes everythingoff it, so be sure that’s what you want to do before you do it.

I can’t stress this strongly enough: Before you reformat a drive, you should back up everything you can, including drivers or updates to software that you’ve sat through tedious minutes (or hours) to download from the Web. You don’t want to have to spend all that download time all over again to get yourself up to speed.