ahtn.htm, Desktop hijacked and locked

[o1sowise]

I was infected by quite a few viruses, some corrected by Norton and some by AVG.
I believe all that remains is the Desktop Lockout.

My Desktop has been hijacked and locked out.
In the middle of my screen, I see a box that says:

Dangerous Spyware
Many viruses were found on your computer, such as: Trojan horse,
PassCapture, etc.
Your personal information can fall into on the "third hands".

Please check up the computer with a special software.
Thank​

Spybot - Search & Destroy 1.6.2 scan finds nothing.
I am at a loss on how to correct.
Any advice would be greatly appreciated.

 

[o1sowise]

Correction

Correction:
A scan just found:

Microsoft.WindowsSecurityCenter_disabled: [SBI $2E20C9A9] Settings (Registry change, fixed)
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\wscsvc\Start
​

I've corrected this finding many times and it keeps on coming back.
I just corrected again and will reboot.

brb