I just had to have my laptop re-imaged and am getting it all configured again. There were some items pinned to my taskbar from the image and when I unpin them, they come back after a reboot. I have seen lots of comments about clearing out %AppData%\Microsoft\Internet Explorer\Quick Launch\User Pinned\TaskBar and removing HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer\Taskband. Also notes about c:\Users\Public\CompanyProfile (which does not exist for me). None of these tricks have worked. I even created a new users and am seeing the same problem on that account. Another symptom I have is that when I default my browser to Firefox, it resets to IE after reboot. I have checked and I cannot see any group policy that is driving this behavior. I am out of ideas.
Installed programs to stick and items I place on my desktop do survive a reboot. In looking around I tried a batch program to help and noticed that if I run these commands in DOS:
taskkill /f /im explorer.exe
start explorer.exe
It resets the taskbar and file associations.