I'm not saying it is a bad program per se, but sometimes a virus will add "search engines" to your Browser, and even in Google, it will add results to the top of the list that are links directly to modified installers that can infect you more. But when I searched for Monkey, every 5th result was regarding some virus that had affected it.
Since you say that your File associations have all been messed up, that's another sign of an infection.
I don't know if there is a way to set all of your associations back to "Default" - You will have to do it one at a time. If the associations won't set to what you want, that's just another indication there may be a virus at work.
If you open Control Panel and go to "Control Panel\Programs\Default Programs\Set Default Programs" you can set each Program to it's original defaults, but only one at a time. Try that for your most used programs including Monkey, and see if it helps. But I highly suggest checking for a Virus, Rootkit or piece of Malware.