Prototype doesn't pissing work. Or so reports say from people in America and European people who have been lucky (maybe) enough to get it early, anyway. Apparently, it says there is insufficient space on the hardrive to install game data (about 700mb of it), regardless of whether there's actually enough space there or not. 

Thankfully, whilst Activision may have dropped the ball here, they have, at least, supplied a workaround. All you've got to do is, well, free up another 700mb and try to start the game again. That's pretty self explanatory, but if you need it phrased condescendingly ('This can be done in a number of ways, including the following...' you can go over to the question on Activision's FAQ. 

Yeah, this is a game that is buggier than Fallout 3 - you can't even start it. It doesn't seem to affect everyone, though (much like how the Fallout 3 bugs didn't affect me), so maybe you'll be lucky. Still, until they get a patch out, which they say will be released 'shortly', what's 700mb? Most demos are bigger than that. Read more »