Unable to Run ComboFix - Please help

First you need to put ComboFix directly on your desktop, not in a folder as you have it here:
c:\users\Chris\Favorites\Desktop\ComboFix.exe

Please double-click the RootRepeal.exe previously downloaded.

* Select File then Scan
* On the Select Drives form select drive C by "ticking" the box for drive C and click OK
* When the scan is complete - highlight each of the following file(s) (one at a time if more then one is listed) by left clicking it. Then use right mouse click and select the Wipe File option only for each file.
o C:\Windows\Temp\TMP00000010BE9A8713A791A205
* After Wiping all files, immediately reboot your pc!

Now use add/remove programs to uninstall:
URL Assistant

If you are not having any other malware problems, it is time to do our final steps:

1. We recommend you keep SUPERAntiSpyware and Malwarebytes Anti-Malware for scanning/removal of malware. Unless you purchase them, they provide no real-time protection. They are useful as backup scanners.They do not use any significant amount of resources ( except a little disk space ) until you run a scan.
2. If we had you use ComboFix, uninstall ComboFix (This uninstall will only work as written if you installed ComboFix on your Desktop like we requested.)
   
   • Click START then RUN and enter the below into the run box and then click OK. Note the quotes are required
   • "%userprofile%\Desktop\combofix" /u
     
     • Notes: The space between the combofix" and the /u, it must be there.
     • This will uninstall ComboFix and also reset hidden files and folders settings back to Windows defaults.
3. Any other miscellaneous tools we may have had you install or download can be uninstalled and deleted.
4. If running Vista, it is time to make sure you have reenabled UAC by double clicking on the C:\MGtools\enableUAC.reg file and allowing it to be added to the registry.
5. Go to add/remove programs and uninstall HijackThis.
6. Goto the C:\MGtools folder and find the MGclean.bat file. Double click on this file to run this cleanup program that will remove files and folders related to MGtools and some other items from our cleaning procedures.
7. If you are running Vista, Windows XP or Windows ME, do the below:
   
   • Refer to the cleaning procedures in step 3 the READ ME for your Window version and see the instructions to Disable System Restore which will flush your Restore Points.
   • Then reboot and Enable System Restore ato create a new clean Restore Point.
8. After doing the above, you should work thru the below link:
   
   • How to Protect yourself from malware!