Wow. What a mess this greatfeedmill hijacker is. My fix required three easy things to do...a Microsoft online scan, Startup control panel and Malwarebytes. The hijack is remedied after the first step. Steps 2 and 3 are for cleanup.
1. Run the online scan. You need to paste both lines of the link directly into your browser if you are currently having the hijack problem:
For Windows XP http://onecare.live.com/
For Windows Vista or Windows 7http://onecare.live.com/
I ran the scan utilility for about 20 minutes or so and I think it only got to 2% complete. This is O.K. I clicked Cancel and it then showed me what the problems were. Select the boxes to repair ALL of the files it identifies (one of which is calc.dll). Once it is done cleaning/repairing, reboot your PC.
After reboot, calc.dll and ntuser.dll are still trying to run but are failing since the files are gone.
2. Download and run startupCPL_EXE.zip
For all Windows
I downloaded and ran the standalone version. I've used this program before and it is fantastic. Go through the tabs, then right-click and delete the references to calc
3. Run Malwarebytes and remove any other issues.http://download.cnet.com/
Note that if you run Malwarebytes first (before doing the online scan), it will find the problem files, but is unable to remove them even after a reboot, so you are left in a hijacked state.
My PC is fixed, so let me know if this works for you too!