I have Windows XP Home with service pack 3--Dell 4700 desk top. I have installed, uninstalled ie7 twice and still receive the above message when I close a window. In the error report it STATES "The following FILES will be included in this error report" C:\docume1newuser\locals1\temp\c29a_appcompat.txt. Does this mean there is a problem with this file? and if so, how do I correct it?Empty the files from the temp folder and see if that helps. You can also download and install IE8 and see if that's any better.I deleted temp files and still encountered same ie7 problem except the file to be reported in error report was DIFFERENT:C:DOCUME1\newuser\local\temp\ae8f_appcompat.txt. Also, I'm unable to go to IE8 at this time. Any other suggestions?See the post in this discussion about disabling Error REPORTING: http://www.pcreview.co.uk/forums/thread-443986.php. I'd try that.I did have this disabled so can I assume this is a critical error? and how might I fix it?Do you have an up-to-date anti-virus program installed? Have you run a scan recently?Yes, I have anti virus and last scanned three days ago.I'm not going to have much time today to research this. If you do a Google search on appcompat.txt errors, you'll get many hits. Based on a cursory scan of Google hits, I wonder whether you're running some program in the compatibility mode of Windows XP. Is that the case?