This may not be the same problem, but has similarities.
I am using Windows 7 Pro. One day my machine started acting strangely after booting. It would take 30 minutes to start running normally.
I tried Task Manager (TM) to see what was running. It would only show me my and Local processes. not all the others. When I clicked on Show All Processes, it froze the TM screen. I started another TM and End Processed the first. TM showed almost no CPU usage, but the CPU gadget on the desktop showed 5-25% usage.
Something was going on I couldn't see.
I checked for virus/malware. I disabled MS Essentials and SuperAnti Spyware with no change.
When Win 7 finally started working correctly, all the processes then showed in TM. I looked for the highest CPU time and that was for SERVICES. I looked that up and found it was for sharing devices/printers.
I had previously installed a shared printer to one of my routers and subsequently gave that printer to my son for college.
I checked my win7 printers and it was still there. I deleted it and rebooted.
BINGO, it booted and ran immediately.
Apparently, Win7 has a "must complete" on the Services process until it completes the search.
I'm guessing that his may also happen with other shared devices that have been removed.
Hope this info helps someone.