-) Go to start, type 'run' and click on first one (it should look like below) and type "%TEMP%" without quotes and press ok. Now delete everything from your TEMP folder and skip the ones it doesn't allow you to delete.
http://www.courses.vcu.edu/tedu500/w...run_window.gif
-) Try a compatibility test, try running as Administrator.
Also, what's the file size of your launcher? If it's not 828kb's then you either didn't download it correctly or something (like anti virus) is partially deleting it). What anti virus do you have?