Random ads pop up where they're not supposed to?

[Graham]

Try this:

Firstly, boot your computer to the Safe Mode menu screen. You do this by repeatedly pressing F8 as soon as you boot up. Once there, use the arrow keys to highlight Safe Mode with Networking. Continue to boot from there, by pressing Enter.

If that's successful, download and run TDSSKiller.exe from Kaspersky Lab. It's tiny, and takes just a minute to run. It hunts down and kills a specific family of rootkits. Here's a link:

http://support.kaspersky.com/faq/?qid=208280684

Regardless of the results, download the free version of Malwarebytes' Anti-Malware (MBAM). Install it, get updates and run a full scan (still in Safe Mode). Here's a link:

http://www.filehippo.com/download_malwar...i_malware/

After that, boot normally and run another full scan with MBAM. It will detect any malware that wasn’t running in Safe Mode.

You should now delete TDSSKiller.exe, as updated versions are often made available. Malwarebytes' Anti-Malware can be easily uninstalled, should you wish to do so, but it may prove to be beneficial in the future.

Hope this helps.