Hi all, I have a notebook with Windows Vista Business and Office 2007, my problem is I can not open any xlsx files by double clicking on them but no problem with xls(office 2003 format) files. Currently I am opening xlsx flies from within a blank excel sheet and it loses a lot of time at my work as i can not open them straight from an email attachment or so. I tried many tricks but all in vain to fix it. Any suggestions please!! Thanks in advance.