I just joined this Forum to help you guys out, I had the same problem late last night, it is SpySherrif along with all it's "buddies" it downloads with it. I disabled everything, thought I managed to fix it, but it came back, it's loading itself through several programs that are going undetected even by current updated scans on your computer. In laments terms it's hiding from you.
Solution:
This is fairly complicated, and I wish there was an easier way to explain it, download Spybot - Search and Destroy, which can be found at download.com, just search for Spybot. Once installed, immediately update the program, but do not scan yet, restart the computer in safe mode (press the F8 key once the BIOS is through with it's POST {all that number crunching at the beginning} and before it starts loading windows with the little bar that goes across, it will give you several options, choose "Safe Mode". Once you've loaded into safe mode run Spybot, it will find several problems including SpySherrif. Now, fix those problems it finds, once it's completely done scanning and fixing, close it. What you have to do now is the hardest part, stay with me. This is a list of programs that seemed to be hiding on my system and seem to be used to reinstall SpySherrif (the bottom line is without these, SpySherrif no longer came back, and they only appeared after SpySherrif hit my computer)
Located in the windows installation directory (typically C:\Windows):
tool*.exe (where * is a random number, there may be several of these)
kl.exe
Located in System32 folder (typically C:\Windows\System32:
paytime.exe
You will need to get rid of these programs if they exist, they aren't neccessary of that I'm sure, I didn't really research them yet, but they were all created within minutes of SpySherrif hitting my computer so I assumed them all bad. Once I got rid of these after the scan and restarted, the problem was gone. I hope I didn't confuse anyone, I'm not good with the explaining portion of this type work, better with dealing with it. Maybe one of the administrators can explain if you don't understand the specifics.