We had an issue over the last view days in which a few selected files where taking a long time to open and often crashing in office 2007.

The issue that was occuring was that the document was looking for a reference file on a decommissioned server.

The way to resolve this issue is within word click on the developer tab, followed clicking document template. You can then click on the Attach button and navigate to the location of the template or the delete the existing file location.

If you are unable to see the developer tab you can sort this by clicking file, options customize ribbon and select the developer option  so that its is showing on the right.