The symptoms of these two spyware infections is that some Windows functions such as Add/Remove Programs and the Task Manager will automatically close before you have a chance to run them.
Also, doing searches for keyphrases like udchniv.exe will cause the Internet Explorer window to suddenly close.
To remove these two spyware programs is relatively easy using Malwarebyte's Anti-Malware program.
However, there is one gotcha: These spyware programs run in the background and prevent you from running the Malwarebyte installation and application.
So here's the trick to use. What you do is rename the mbab-setup.exe file to something like fred.exe. This will allow you to run the installation program since the spyware program is actually looking for the filename mbab-setup.exe.
Now once the program is installed, you'll also have to change the name of the application as well before running it since the spyware is also monitoring the application filename.
Navigate to C:\Program Files\Malwarebytes' Anti-Malware\ and rename the file mbam.exe to fred.exe or bob.exe or any of your favorite relatives. :) Run the renamed application filename and Mal's program should remove both udchniv.exe and atthdop.exe