What you're describing sounds an awful lot like what I had to fix on my parents computer. My dad tends to just click whatever pops up, and as a result of that, they got some toolbar thing installed that was actually malware. Every broadcast back and forth got hi-jacked and routed through a third party site that send back additional pop up ads with the response.
Their "came free with the computer 5 years ago and never saw an update since then" virus scanner never picked it up. And it was so deeply embedded, only running a boot level virus checker managed to clean it out. Personally, I prefer kaspersky
for this. There's searchable information for how to create a bootable USB stick that you can boot to instead of windows and then use to really ensure your machine is clean.
Alternatively, another tool I use for work might come in handy for you. Fiddler
is a tool that shows you every message (HTTP Post/Get) your machine sends out and it's incoming response. Should be able to identify what's being transmitted back and forth by going through those logs.
But your best bet, since it's a corporate machine that's locked down by IT policies, is probably to just file a help desk ticket with them to have them confirm there's no extraneous issues with your machine.