Windows Security Suite

My guest account starts to act strange since yesterday. a pop-up appears every time the guest account is used. Together with this pop-up is a "pig-like sound" like that of Kaspersky. I have performed a scan using AVG 8 Free Edition but it was not able to find any threat so is my Malwarebyte's Antimalware.

Using Task Manager, I learned that it registers as "Windows Security Suite". I searched it using Google and it lead me back "home" (here at Bleeping Computer).

I was just wondering why Malwarebyte's didn't find any threat.
I performed a scan using the Admin account. Would this make any difference?

Thanks in advance. . .

Hi,

I'm going to redirect you to the HijackThissection of this forum. This, because it's a deeper infection.
Read this page and follow it's steps: http://www.bleepingcomputer.com/forums/t/34773/preparation-guide-for-use-before-using-malware-removal-tools-and-requesting-help/

Please give them a link to this topic.

Good luck.