How to go back to default file reader for files created by Fortran

Hi,
I create (external?) data files in Intel Fortran by the WRITE command in the file system.
Default reader for these files is Windows Shell Common DLL. For one file extension, .al1, the default reader has been changed to WordPad, which means that the file extension .al1 is not visible when the files are listed. I have read about very similar problems being solved in the forum and I tried to get back to the default by gessing that my files were of the type DAT. However no change could be seen.
How can I solve this "problem"?
Best regards
zantex111

Hi,
When you try this, you are asked to give the program you want. I don't know how to find "Windows Shell Common DLL"!
Best regards
zantex111

Hi,
To find shell32.dll I had to choose 'All files' Instead of default *Programs' when I got to C:\windows\system32. When I load shell32.dll, I get 'Windows Shell Common dll as an alternative in the box, but it doesn't seem to do any change. When you repeat the action the new choice has disappeared.
Best regard
zantex111

Hi C-11,
I went to your suggested link 'Remove File Type Associations in Windows 7', loaded the program, found my extension '.al1' in the list, pressed remove AND GONE IT WAS. My files got the extension '.al1.' back and everything seems OK.
Thanks a lot C-11 and whs!
Best regards
zantex111