I think the simplest way is to install BOINC there. If your OS partition is just for the OS, that may not be that bad. If you actually have the OS and installled software there with data only on F:, then that may not. I don't recall a simple way to point BOINC data files to a separate location from BOINC itself. It might could be done by doing something you'll get told you DON'T want to do - edit one of the BOINC files that has a reference to that (assuming there's a separate entry just for that). Even if that's possible, any problems and that's the first thing you'd have to change back.

Hi T.Rob.

This is on the feature list for the next version. Until then, it can be done (the datadir command line argument), but it's really too much trouble to bother with. I advise you to wait, and install BOINC entirely to the data partition for now.