Instructions
Option 1
1) Open the program which was originally used to create the file. For instance, if the file is in .xls format, open Microsoft Excel.
2) Most programs will allow you to choose "Save As", "Export", or a similar option from the File menu and save the file in an alternate format. If it's not under the File menu, check the other menus and toolbar buttons. If none of this works, consult the software's "Help" menu or documentation on how to save files into a different format.
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Option 2
1) Do a web search for "convert file". You might also include the format of the file in the search terms.
EXAMPLE: "convert mov to m4v".
IMPORTANT: IT Help Central cannot support or endorse third-party websites. This is merely presented as an alternative to "Option 1" listed above. IT Help Central cannot assume liability for problems or loss of data resulting from file conversion on websites.
CAUTION: Do not use third-party websites to convert files containing sensitive or confidential data!
2) Follow the options on the website to convert the file. It may take several minutes for the results to come back.
Outcome
After you have saved the file in the alternate format, try opening the file in the desired program.