If you click on an email attachment, your browser will most likely download it instantly. If you'd like to open the attachment instead, you can adjust your browser settings.
For Chrome users:
Download the file type once, then right after that download look at the status bar at the bottom of your browser. Click the arrow next to that file and choose "always open files of this type".
Now the file type will always open using your default program.
To reset this feature, go to Chrome's settings / advance settings. Under the "Download" section, you'll find a button to reset all auto downloads
For Internet Explorer users:
Click Start, then Programs (or All Programs) and find Windows Explorer.
Now, click Tools > Folder Options and click on the File Types tab.
When the list appears, find the file extension in the list, click it to highlight it, and then click Advanced. You can now see the Edit File Type dialog box
The Edit File Type dialog has two options that decide how your Word documents open: Confirm open after download, and Browse in same window.
For Firefox users:
Click the menu button and choose Preferences.
In the General panel, go to the Applications section.
Select the entry for the file type you want to change.