it keeps saying install failed, wont let me press install again, i try to uninstall and it does nothin?

I'm guessing you are using gog galaxy? If that is the case, and it's the same error I've come across, there is a simple solution. You need to restart galaxy. To do this, there are at least two ways I know of. Either reboot the computer, or close galaxy through task manager (ctrl+alt+delete). Closing galaxy through clicking the x button will do absolutely nothing to fix this issue. I hope this helps.

Might also be helpful if you mention the specific game and OS you;re using.

europa universalis rome gold using win 8. so its compatible. i tried turning gog off through task manager, still getting the problem. i will try a reboot of computer.

Lack of free space could be the problem as well. Make sure you have more than enough space before installing the game. I remember I had only few GB left on my Windows partition and Galaxy went mad even with some game updates ; )
and would be helpful if you give us some more informations, OS, game you're having problems with..

yeah i already mentioned my OS an what game it is. i also have 1 tb spare space.

Have you tried installing it OUTSIDE of galaxy?

You can also end Galaxy through the tray icon (bottom right, near the clock...). Right click and choose "Quit" or "Exit" (at work right now, so I can't check).