Game wont start

Hey there, alas, there are a couple of things that are causing the game to not work on your girlfriend's system. It looks like her graphics card drivers have not been updated since 2013 and does not have the required dedicated memory to launch and run Don't Starve Together. (Her card only has 64 MB - DST requires 256 MB or higher). Here are a couple of troubleshooting steps you can take: 

• If her computer has a dedicated graphics card like an AMD Radeon or NVIDIA GeForce card installed, she will have to go into her AMD or NVIDIA Control Panel and force her dedicated GPU to launch and run Don't Starve instead of the integrated Intel HD card.
   
• If she does not have an AMD or NVIDIA card, ensure that the Intel HD card's drivers have been updated: https://downloadcenter.intel.com/
   
• Please ensure that she is running the Steam Client in administrator mode when installing/playing Don't Starve Together: http://windows.microsoft.com/en-ca/windows7/how-do-i-run-an-application-once-with-a-full-administrator-access-token

Should the steps above not help, your best, next step is to contact Steam Support for a possible refund due to system incompatibility.