Yo Kass answered It depends what files he actually sent you to be honest. Is there some sort of installer executable file? Or a zip file you need to unzip?To be honest, I'd be surprised if you could simply share an entire software suite through Dropbox.For starters, Photoshop is huge. Secondly, it won't run on your computer unless you have the correct license.It sounds more likely that he's sent you some files that pertain to Photoshop, rather than the entire package.And to be honest, I'd recommend purchasing your own version.Alternatively, check out Sketch - or if you want something free and browser-based, there's also Sumo Paint.