It could be possible that it is hiding in system restore!
start > R click My Computer >properties > system restore tab > check the turn off system restore box and ok out!

Once done retry your anti-spyware/malware programs....if still no good then you must look at the possibility that it is hiding itself under a different name within the services.

start >run and type

services.msc

click ok

very carefully run through each item listed to see if you can find something related to the zedo crap......compare with what your programs are showing it to be. then stop the service and then it can be deleted! Be sure of what you are deleting though or you might have to reinstall some programs.

Trendmicro has a very good and safe online scanner that might be able to remove it from your system....your system restore needs to be off..... go there and run the free scanner!

Trend Micro HouseCall - Free Online Virus and Spyware Scan - Trend Micro USA