Fast Forward

Help File: Freeing Up Disk Space After a Vista Update, A Bogus Spam Defense

By Rob Pegoraro
Sunday, June 14, 2009

QIs it true that Microsoft's Service Pack 2 update for Windows Vista can free up disk space by deleting older patch files?

AThis new update -- it should arrive as an automatic update soon, or you can download a complete installer from its Web site -- includes a "Windows Component Clean Tool" that can remove files left behind in the installation of SP2 and earlier Microsoft updates.

(You may also see this called the "Service Pack Clean-up Tool" or referred to by its filename, "compcln.exe." Not that there's much documentation of the program; Microsoft's own technical notes barely mention it.)

To run this program, click Vista's Start menu, type "compcln.exe" into its search box, then hit Enter. After you click through Vista's User Account Control are-you-sure dialog, an old-fashioned, text-only DOS prompt will open and warn you that this program will make your installation of SP2 and earlier updates permanent and irreversible. Type "Y" to agree, and the DOS window will close when the program finishes the job.

On one Vista system, it only needed four minutes to free up a gigabyte or so of disk space, with no evident side effects. It's a nice little extra -- even if having to run a DOS program in 2009 is ridiculous.

This e-mail says that adding a fake address-book entry at the start of the alphabet -- AAAAAAA@AAA.AAA -- stops viruses from sending itself to people in my address book.

Nope. For one thing, why would a virus stop if it encounters a bad address? Remember, the virus is using your computer and your bandwidth. It doesn't care about being efficient.

For another thing, any alleged fix this old (the myth-busting site dates it to 2001) would have been noticed by virus authors long ago. These people have a cockroach-like tenacity when it comes to their "work."

Rob Pegoraro attempts to untangle computing conundrums and errant electronics each week. Send questions to The Washington Post, 1150 15th St. NW, Washington, D.C. 20071 or Visit for his Faster Forward blog.

© 2009 The Washington Post Company