You might get something from the Windows Application Event Log that would identify the module that's failing.
It might also be helpful if you'd list the steps in the action, or post a copy of it (assuming that's acceptable). There are a few long-standing bugs that could be responsible - for example making a new grayscale document from the clipboard in an action was known to corrupt things up through Photoshop CS5. That's been fixed more recently.
Check you Windows 7 reliability log and look the the Photoshop failure see what the faulting module is. If you do not know how. Type rel into the start button search you should see View reliability history up top. Start it. Look for a day with a red x if you see its Photoshop double click Photoshop to see what failed.
Thanks for the replies. I will check these out when I return to work.