You didn't mention whether other attachments open or not, but if others also don't open, here is a tip that can fix many a program.
Open a dos box, and type in SET.
Make sure that both TMP and TEMP have definitions, and that they are valid directories. (Often C:\Windows\Temp.) (It is also a good idea that the all names on the temp path are 8 letters of fewer, and do not contain spaces. Eg. "C:\John Smith\Temp" would be a bad choice.) If they are not properly defined, you must edit AUTOEXEC.BAT and reboot after fixing it. AUTOEXEC.BAT should have lines like:
SET TEMP=C:\WINDOWS\TEMP
SET TMP=%TEMP%
or
SET TEMP=C:\WINDOWS\TEMP
SET TMP=C:\WINDOWS\TEMP
Make sure that the directory really exists, and if it is on a securabledrive (not likely with Windows 98, but this tip may be read by a Windows 2000 or NT user), make sure the user has full access. If not, fix the problem by creating and unsecuring the directory.
(This is also a good time to verify that the path includes the Windows and Windows\Command directories, and that winbootdir and windir both point to the Windows directory. If not, seek help.)
Make sure the hard drive has sufficient room. If there is less than 100MB of free space, make sure that the free space, less the space taken up by the files in the recycle bin is greater than 50MB. (The reason why, although Windows may report free space, a lot of programs hang when they try to use it if the free space is occupied by files in the recycle bin.)
If the above does not fix your problem, then as someone has already suggested, try to save the file to a hard drive. Display the file in Explorer, and right click and select properties. The file type should be "Microsoft Excel Worksheet", and the file extension should be .xls. If the extension is not .xls, then the file is not a standardly named Excel file, but for some reason the other machines are set up to read them a
