I agree with the OP, I tried 3 or 4 download offers, none ended up paying out. Some of the offers actually came with malware (which I didnt download).
In other words, steer clear of the download offers and watch videos & do the surveys (my view and ampario usually work. the ones on the "take surveys" tab work as well, if you get dq'ed you still get 5 credits usually)
I recommend after uninstalling the programs (I waited 3 days and no credits, even opening the programs, etc) that you run a good malware/spyware program (Hitman 3 comes to mind, it has a 30 day free period where it removes any tracking cookies, trojans, adware,etc)