getting 514 off the system so that you can install 513 takes some doing and I wish I could remember how I did it.
I think I did a big reinstall of windows 7 so that you basic loose everything, but I dont think you will want to go that far.
I think there is away in the windows install system which shows what update have been downloaded and install, I think you find the one to do with the driver or graphic card and tell it to uninstall them.
if you get it to unistall 514, then try the 513 version and it should hopfully work.
I know thats not very clear, but it might help a bit.
Dark Physics makes any hot drink go cold.