Funny you should bring this up, as we were just having a remarkably similar problem at work today. We had a whole bunch of machines that suddenly exhibited this same behavior after getting a recent (critical) update. A few questions: are you able to open documents by double clicking on them from within Windows Explorer (or open URL's from within IE?) Also, do you have any scanner software (HP in particular) or Kerio Personal Firewall? Also look in your task manager for multiple (or even single) instances of the process "verclsid.exe" (which are central to this problem.)
Once we discovered this
MS article we were able to repair the issue. So far, that had completely fixed it for us. We just had to apply the registry change and reboot the machine.
Jam it back in, in the dark.
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