Perfect! Download Spybot Search and Destroy. It's free, and I've you have that, update it and run the scanner. If that for some reason doesn't work, you download AVG Anti-virus software, also free for home use, update it (the definitions) and run a deep scan.
This will take time to complete, but will find malware and possibly ad creators infected in your computer. All free.
I assure you this is not pH doing this.