Windows XP [Electronic resources] : Visual Quickstart Guide, Second Edition نسخه متنی

Associating Documents with Programs

, for example) without making you read the Type column in Explorer.
Extensions make it plainer to, say, choose among Photoshop, Paint, Internet Explorer, and Windows Picture and Fax Viewer to open .jpg (JPEG) files.
If a newly installed program hijacks an extension''s association without asking your permission (both rude and common), you can reassociate the extension with your preferred program.
If you don''t learn about extensions, you''ll remain mired in beginner status and pester people with trivial problems.

Viruses and Extensions

Viruses disguised as innocuous attachments often arrive via email. A virus file with the extension .exe is a program that runs when you double-click it, infecting you. (Some other extensions are dangerous too.) Virus writers will try to trick you into thinking a file is safe by naming it, say, iloveyou.txt.exe. If extensions are hidden, you see only iloveyou.txt, which appears to be a harmless text file.

Even with extensions showing, the file FreeMP3s.txt .exewill appear to be harmless if the embedded spaces hide the .exe extension in a narrow column.

To show extensions:

In Windows Explorer, choose Tools > Folder Options > View tab > Advanced Settings list > uncheck Hide Extensions for Known File Types (Figures 6.30 and
6.31 ).

To change the program associated with an extension:

1. In Windows Explorer, choose Tools > Folder Options > File Types tab (Figure 6.32 ).

2. In the Registered File Types list, select the extension that you want to change.

3. Click Change.

4. In the Open With dialog box, select another program to associate the extension with (Figure 6.33 ).

5. Click OK in each open dialog box.

Tips

The Details section in Explorer''s task pane contains file-type information for the selected file.

Some file types have multiple extensions (/l and .jpg/.jpeg, for example). Repeat the association for each form of the extension.

If you double-click a file with an unknown extension, Windows lets you choose a program or try to look up the extension on Microsoft''s web site (Figure 6.34 ).

If you want to open a file with a program other than the associated one (without actually changing the association by reassigning the file type), right-click the file''s icon; then choose a program from the Open With submenu (Figure 6.35 ).

To change the icon for a file type, follow steps 1 and 2; then click Advanced > Change Icon (Figure 6.36 ). You also can find icons by using Search to look for *.ico files. Unfortunately, most icon collections are hidden in .dll files. shell32.dll has a bunch, but finding others will take some work.