how are spywares architected
i understand that some websites knowingly set some cookies to do tracking and if other websites retrieve those third-party cookies, they may tend to open new pop-up browser instances with relevant/irrelevant websites.
having said this, i am unable to understand the following-
1. some times, a browser instance gets launched in my machine for every 5 minutes showing some website- how does that happen ?
2. i also see "shortcuts" being placed on my desktop that are essentially links to some casino websites - how are these shortcuts created ?
i have never installed any software on my laptop and it is a clean anti-virus protected laptop and i just use IE and MS office applications.
if the questions are trivial, can someone point me to an article that explains the technical works of all this stuff ?