Excel Worksheet Gets Renamed As As .xls[Sheet When You Open It From ASP

I am using ASP to open a excel file.

I've noticed that Internet Explorer adds a number in square brackets to files downloaded from the internet and opened directly (i.e. by clicking 'Open' and not 'Save'). This creates a big problem with downloading Excel spreadsheets as square brackets are not a valid filename character inside Excel worksheet name.

When I click open, it opens the excel sheet with the sheet name
as .xls[Sheet and the excel filename as Sheet[1].xls.

Then we get the following error....

While renaming a sheet or chart, you entered an invalid name. Try one of
the following:

- Make sure the name you entered does not exceed 31 characters.
- Make sure the name does not contain any of the following characters:
: / ? * [ or ]
- Make sure you did not leave the name blank.