This a particularly nasty spyware. Firstly run MalwareBytes or Spybot to remove most of it. then you have to manually remove some files.

This link has instructions. http://www.bleepingcomputer.com/virus-removal/remove-windows-system-suite

After this, Windows may still report that an Antivirus program is currently installed, reporting it as Windows System Suite.

Do the following:

In Control Panel click on Administrative Tools, then Services, from the list of services find Windows Management Instrumentation right click mouse and from dropdown list stop the service.

Find folder C:\windows\system32\wbem, inside this folder identify the repository folder and delete only this folder (the repository folder) from your computer.

In Administrative Tools find Windows Management Instrumentation service again, and re-start the service by right clicking mouse and pressing start from dropdown list. Restarting this service re-builds the repository folder database on your computer, which should now only contain information about your currently installed antivirus & firewall programs.

To reset the Windows Security Centre you must re-boot your computer.

You should then be able to reinstall you AV program.

However, I was still having trouble installing AVG, it kept failing to start the AVG Service at the end of the install.

Following the mentioned thread and the directions for windows registry corruption:

“Please open Windows Registry Editor
- open menu Start -> Run -> enter “regedit” and cofirm OK
In opened Registry Editor find this key:
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Image File Execution Options
Check that none of sub-keys have name like AVG processes (all AVG processes):
avgam.exe
avgcfgex.exe
avgcmgr.exe
avgcsrva.exe
avgcsrvx.exe
avgdiag.exe
avgdiagex.exe
avgdumpa.exe
avgdumpx.exe
avgemc.exe
avgfrw.exe
avgfws8.exe
avgfwwiz.exe
avgiproxy.exe
avgnsa.exe
avgrsa.exe
avgscana.exe
avgscanx.exe
avgsrmaa.exe
avgsrmax.exe
avgstrma.exe
avgstrmx.exe
avgsysta.exe
avgsystx.exe
AVGToolbarInstall.exe
avgtray.exe
avgui.exe
avgupd.exe
avgwdsvc.exe
fixcfg.exe
And remove them from registry. ”

I deleted those entries in the registry and, finally I was able to install successfuly the AVG 8.5.

You can download AVG Free from here  then run the download file by clicking Start, Run, selecting file where it was saved then add the following switch

/REMOVE_FEATURE fea_AVG_SafeSurf /REMOVE_FEATURE fea_AVG_SafeSearch

before clicking OK to run the install.

For a review and instructions click here