Hit ctrl-esc-del and bring up the task manager. I've had this happen on occasion and found that the program is actually loaded in the task list but not running properly. In any event, I'd first try killing any extraneous processes, virus checker anything run ning in the background and see if by chance the installer will run. You m ight also try booting into safe mode and seeing if it will run then which would probably narrow it down to some driver you have loaded. Next in terms of time consumption, re-download the file and try it again. If that doesn't work, time to reinstall the OS.

"Democracy is a pathetic belief in the collective wisdom of individual ignorance." - H. L. Mencken