I reinstalled revit recently, because i did some changes in my computer, so when I open revit now it says that im running it on viewer's mode, and that the program is unlicensed (I have a student license). What should i do, please help.
Welcome to the Autodesk Discussion Forums and thank you very much for the screen shot! It was very helpful.
The "License unavailable. Autodesk Revit Architecture 2012 is in viewer mode" error is fairly common and has been previously documented. Check out this thread.
Let us know if this works for you, and if so, please mark it as a solution.