Strange Ads

[Northeast]

Hi guys,

I have this black colour ad with white colour text at the top right hand corner when i visit some websites.
The ad's just appears for about 10 seconds or so and then disappears. I haven't tested out a lot of websites and it does not appear in this avast forum site or other antivirus forums and google search page. It's not a major problem as I not sure if this is normal as has anyone experience the same black ad appearing on there computer.

I have scan my pc with surperantispyware, Malwarebytes, and avast and all three has come up clean and no signs of adware. Can someone please help me fix this or tell me if this is normal.

thanks.

[micky77]

What the ad for, what is it advertising ?

[nmb]

post a screenshot of it, may be.

[Hammerhead]

Sorry i posted in the wrong section, please delete this.

[Northeast]

Hi micky77, and nmb, thanks for your reply too this thread. I was a bit worried yesterday about this as I thought they were pop up ad's but this evening I just found out it was firefox's plugin Ghostery that was blocking those ad's from appearing on the website.

I just install Ghostery not long ago and not sure in what it did. So thanks for reading this thread and helping me out when I thought I had adware.   

thanks guys.

[nmb]

you are welcome.