Treat is like any other infection. Here are a couple of ideas:
1. Perform a full ODS of Memory for Rootkits, Running Processes and All Files. Be sure you set GTI (on the Performance tab) to Very High
2. Run GetSusp (search the KB to find it). It will give you a list of suspicious files. Don't delete them since some of them will be false. But now you'll have a list of files that you can submit
3. If you still come up blank, remove the drive from the PC, mount it in a SATA case, plug it into another computer and perform #1 on a different computer's OS.
We have seen the same blocked BO attacks since 02/28/14 though at a slightly different location:
C:\Program FIles\Internet Explorer\iexplore.exe:NTDLL.kiUserExceptionDispatcher::8ba0068
C:\Program Files\Internet Explorer\iexplore.exe:NTDLL.kiUserExceptionDispatcher::7990068