Help File

Q When I right-click a PDF file and select "Open with," my Mac lists Preview, Adobe 9, Adobe 8 and Adobe 7 as options. How do I get Adobe 8 and Adobe 7 -- removed from the Mac a long time ago -- off this menu?

A This can happen when a system database called Launch Services gets scrambled.

Apple doesn't provide a simple way to fix this, so the easiest remedy may be a third-party utility called Cocktail. It sells for $14.95, but you can download a trial version from its developer's site (http://maintain.se/cocktail).

To clean up that "Open with" menu, start Cocktail, click its "System" tab, select the "Databases" heading and click the "Rebuild" button next to "Rebuild Launch Services database." A "Restore default file associations" checkbox, if clicked, will also wipe out any custom open-with choices you've added.

While you've got Cocktail around, see if it can fix any other system ailments on your Mac. Among other things, it can help tidy up a hard drive by deleting old log and cache files and adjust interface quirks like the Help program's habit of staying in front of every other program.

On my new HDTV, movies still show up in letterbox. I thought getting a wide-screen set would end that.

The movie industry has come up with multiple definitions of "wide" since it began adopting wide-screen formats in the 1950s. Many of these surpass a high-def screen's aspect ratio of 16 to 9 -- or 1.78, as these things are noted on the cases of some DVDs.

For example, my copy of "Office Space" has an aspect ratio of 1.85, while "The Empire Strikes Back" is wider yet at 2.35. Both will appear on an HDTV or a widescreen monitor with black bars above and below -- letterbox -- but they will be smaller than on a standard-definition screen.

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 robp@washpost.com. Turn to Thursday's Business section or visit washingtonpost.com anytime for his Fast Forward column.