let troubleshoot it in different way..... You could do this yourself or if you prefer i could look into your system via Teamviewer.. DIY
1. First of download Process Monitor
and run it.
2. You would see a stream of process activity going on ...or you will have an option of filtering the results.... We need to choose "Process name" from the first drop down is and in that textbox enter "DllHost.exe"... Click Ok
3. run Picture viewer and try browsing 2 or 3 images where it slows down.... You can watch process monitor windows what is happening.....
4. Now stop the scan (its a small magnifying glass) and then go to file and save using the default option mentioned there.
5. send the .pml file here to review.