The "Open With" option: Sooner or later you'll open a file with the wrong program, the file won't open correctly, and worse, every time you try to open another file like the first one, the same erroneous program tries to open that file to no avail. (Didn't see that little check box, didja?) This can be repaired tediously in Explorer's File Types dialog box, but another way to do it is to go behind Explorer's back to the old Win 3.1 utility, File Manager. (Yes, it's still there, but Windows makes it hide in the closet.) Access File Manager by going to Start/Run, typing WINFILE in the Open box, and press Enter. When File Manager appears like a ghost from Windows Past, choose File, Associate. and fill in the box at the top with the file extension that's giving you fits. Scroll to the top of the list of file types and select (None). This removes the association from your system. You can also use this technique when a newly installed application hijacks a file extension, as when both Netscape and MSIE fight over who gets to play with files ending in .HTM or .HTML. (Don't decide to use File Manager to deal with your files; this relic doesn't know about long filenames, and will inevitably conflict with Windows if you decide to use it. NT 4.0's File Manager is, however, long filename-aware. Go figure.) PC Magazine offers a free utility, Freedom of Association, which lets you rework file associations easily. Now, what's the tedious way? In Explorer, select View/Options (or Folder Options in Win 98), click the File Types tab, look for the file type in question (look for the application name if the file type isn't visible), click it, click Remove, then click Close and you're done. (There's also a long and even more icky Registry hack that takes care of default associations, but you don't want to deal with that.)

Win 98/ME users have an out that Win 95 users don't. Find a program that has an incorrect file association with it in Explorer. Click it once to select it, then hold down the Shift key while right-clicking it. Choose Open With. Select the correct program, check the "Always use this program to open this type of file" box and click on OK. Or, if you don't find the program, click on the Other button and navigate to the correct program on your drive. Much easier than the older alternatives.

A good rule of thumb is, when you see the Open With dialog box, immediately click the Cancel button. When Windows runs into an unknown file type, it often tries to guess what application would best be used to open that file. Usually its guess is bad, and worse, the Open With dialog box permanently associates that bad guess with the unknown file type. Don't make the associated mistake of thinking that unknown files aren't important. They usually are.

See the "Always ask before opening..." option? No? If you've disabled it (oops), you can reactivate it through modifying the entry in the File Types association Window. Go to an Explorer window, say by double-clicking My Computer. Select Tools, Folder Options, or View, Folder Options in Win 98. Select File Types. Scroll down and select (left-click once) the offending entry. Click Advanced. Ensure that "Confirm Open after Download" is selected. Click OK and you're there. Now, don't do it again!

Opening a file with the wrong application can result in a corrupt display of the file's information and content. Whether this happens automatically or by your own error, do not save the file -- this can permanently foul up the file. Close the file and its associated app, and manually open the file in its proper application.

You can change what application launches a particular type of file easily enough, but you might want to have more than one program associated with a particular type of file. For instance, you usually open HTML files in a Web browser, but on occasion you'll want to open them in an HTML editor or text editor. In Windows ME, 2K, and XP, you can make this change on the fly. Right-click the document icon and choose "Open With" or "Open With," "Choose Program." Select your application from the list. If it isn't there, click Browse or Other, navigate to and select the desired application, and click Open. Don't click "Always use this program to open these files" check box. The application you use will appear on the Open With submenu the next time you click a file of that type. NT and 9x users can download OpenExpert 1.40 from www.baxbex.com/products.html; this utility allows 9x/NT users to do the same. (The program is $20 for corporate users but free for us slobs.)

Sometimes Windows insists on automatically opening (instead of just saving) a file when you download it, most commonly a .ZIP or graphic file. Regain control of this by going through Explorer, choosing Options (or Folder Options in Win 98), and clicking the File Types tab. Select the file type from the list. Now click the Edit button, and in the resulting Edit File Type bos, find the checkbox labeled Confirm Open After Download and make sure it is checked. Click OK and click OK again to close the Options dialog. The next time this kind of file comes down the pike, Windows will ask permission before opening the thing onto your disk.

There's also a way to make Windows open a file in any of several applications. In Explorer, go through View/Options (View/Folder Options in Win 98), click the File Types tab, and select the type of file you'd like to open in multiple apps -- say, .GIF or .TXT files. Click Edit. Under the Actions list, click New to open the New Action dialog box. In the box, type the command you want to appear in the context menu -- for example, if you've chosen .TXT files and you want to edit them in WordPad sometimes, type EDIT IN WORDPAD. In the box labeled Application Used to Perform Action, type the full path name of the program you want to use to open this file type, or use the Browse button to find the app and then click it. Add quotation marks around the path name if the name contains long names or any spaces. With some apps (like WordPad), you might need to add a space followed by the characters "%1" after the path name. For example, the WordPad application line should read: "C:\PROGRAM FILES\ACCESSORIES\WORDPAD.EXE" "%1" Click OK and then Close twice to seal the deal. Now, when you need to open a file in an alternate app, you just right-click the file icon and choose your new command. There's a way to do this in Win 3.x also; check the July '99 issue of PC World for details.

Make your files 'fess up to what they are by showing their file extensions at all times. Inside an Explorer window, select View, Options (or View, Folder Options). Click the "File Types" tab, and under "Registered File Types," select the file type for which you want to display extensions. Click Edit, select "Always Show Extension," and click OK twice.