Windows 7 and X3

I’m using Windows 7, Word 2007 and EndNote X3. Whenever I’m in Word and  click the EndNote tools I get the message “This action cannot be completed because … Microsoft Word program is not responding; choose “Switch To” and correct the problem”. At other times “EndNote is waiting for user information”

Is this a particular incompatibility issue with the combination of software I’m using. I could upgrade to X4 - would this fix it?

Per the EndNote support site, X4 is compatible with Windows 7 (see snippet below from http://www.endnote.com/envistaand7.asp) but some issues are noted for X3.  While their notes claim “no major compatibility issues” your problem does seem to be “major”.  You don’t mention whether your computer is 32-bit or 64-bit as the latter does seem to create problems noted by assorted forum users.  You could conduct a minor test by backing up your EndNote library and assorted files, remove EndNote X3, then download and install the trial version of EndNote X4 from http://www.endnote.com/endemo.asp (which runs for 30 days) to see how it runs with WIndows 7 on your computer.  If it runs fine (as it seems likely to happen) you can upgrade your software.  If you encounter further problems you can contact tech support.

Windows 7 notes for all versions of EndNote:

EndNote X4

EndNote X4 is compatible with Windows 7 and Vista.

EndNote X1/X2/X3

We have informally tested EndNote X1, X2 and X3 with Windows 7, and had reports from many customers using Windows 7. No major compatibility issues beyond the currently known general issues with Vista and 7 were found. EndNote versions prior to X1 have not been tested for compatibility as these older versions were no longer supported when Windows 7 was released. Earlier EndNote versions may be upgraded for continued compatibility.