Clever solution cannot open xls file directly

I always use Excel spreadsheets in my daily work, never had a problem, but one time a friend brought a file in XLS format, said that on his computer double-click can open with Excel program open, but open the page is blank, in fact this document is content, let me see, So I experimented on my own computer, and there was no problem, in order to insure, I have saved another, friend take back, still such a problem, at the same time found a lot of XLS format files have appeared such a problem, it seems that his computer has a problem, there is no way I went to his home to find out why. First of all, the virus did not solve the problem, it seems that the file is associated with the problem, to view and repair the file association, or not. How can this be done? Do you want to reinstall the system?

Finally, if there is a problem with the settings in Excel, you open the Excel program and view it from the Tools menu with the Options dialog box, and on the General tab, you find a "Ignore other applications" item (figure). It's not ticked in front of it, I tried to tick it, and then click OK. This time again to double-click Open before the xls file, ha normal opened. The problem is finally solved. The friend who has this aspect question also tries!