Chrome and Firefox show Alerts, Full-tab Ads and Redirect

Both browsers I have installed, show the same symptoms..

Pop-up alerts claiming you have to download this or that software to "stay safe" which can only be closed by force by closing the browser from the task manager.
Random new-tab Ads,
Random redirects upon goodle search, to random search engines.

So far I've tried:
Look for new unknown plugins intalled in the browsers - don't see any.
To uninstall any suspicious software - can't find any.
To look for suspicious processes running in the background - didn't find any.
Scanning my computer with Avast and Malwarebytes, they don't find anything.

Any suggestions would be greatly appreciated.
Thanks.

Cracked - Illegal Software

May I draw your attention to the topic: ALL USERS OF THIS FORUM MUST READ THIS FIRST, which you should have read before posting for help. The section here explains why we bring this to your attention.

If you wish to receive help from us, you must remove any and all of the following from your computer:

• Illegal software
• Cracked software
• illegal software key generators

Once the software and/or keygens have been removed, if you still need help, please start a new thread... include a link to your closed topic and include NEW FRST logs :

• FRST.txt.
• Addition.txt.
• Details of the problems you're experiencing.

Wait for a new helper. Do not reply to your topic before a helper has replied.

This topic is now closed.