you need to be a little more specific with "small application", does it contain any drivers? services? etc. If it is a simple exe file that runs on the stick then it should be no problem. You would need to check for the existence of the usb token path, do a file search for (drive):\whateverfile.xxx, the same for acrobat reader, simply search the computer for acroread32.exe and the version minimum 4.xxx, set an install condition of ACROPRESENT<>"" and copy the contents of the search (the install path, should be done automatically) into the string. as long as something is there the equation evaluates true and the install runs. you need to be sure however that the software itself runs on all desired systems without system specific parts or you need to know exactly what they are. as far as running the pdf afterwards, simply create a custom action(installed with product and point it to the pdf file) as long as Acrobat is present, the pdf will open.
