Hi there.
I suggest you make sure that you are running the latest diplay drivers for your GT240.
You can get them at the
Nvidia download center here.
Just select the following from the drop-down boxes.
Product Type: GeForce
Product Series: GeForce 200 Series
Product: GeForce GTS 240
Operating System: Your current operating system.
Language: The language that you want the setup to be in.
Then click the search button.
Click download on the next page. Once downloaded, run the setup and it will install the driver. You will need to restart to finish the process.
Slasher_X