I searched for this error on Daniweb, but I didn't find anything here, so I thought I would post the fix.
It seems that the above Microsoft Security Update (KB953838) breaks something in Microsoft Dynamics CRM. Microsoft documents this update as a "Cumulative Security Update for Internet Explorer 8 Beta 1 for Windows XP"
When a user tries to open a record, a dialogue box appears asking the user to save the file "Blank.aspx", instead of opening the record.
The current fix for this is to remove the update by going into Control Panel -->Add or Remove Programs --> Ensure the "Show Updates" box at the top of the screen is ticked, scroll down to find the entry Security Update for Windows XP (KB953838), and then remove the update.
After rebooting the machine, CRM then runs correctly.
Below, I have included a link to the 2 forums I found as a reference.