We can help but we need to get more information about your system.
If you could generate a dxdiag file and send it to us in an email to firstname.lastname@example.org then we can better assess whether or not it's Windows 8.1, or another component such as an outdated driver.
To create a dxdiag.txt in Windows 8, just follow these steps
From the Windows desktop, press the Windows key and the R key to open the Run window.
In the "Open:" field of the Run window, type "DXDIAG." Click OK or press the Enter key to open the DirectX Diagnostic Tool (if prompted to check if your drivers are digitally signed, clickYes).
In the DirectX Diagnostic Tool window, click the "Save All Information..." button.
In the "Save As" window, the DirectX information will be saved as a text (.TXT) file. Designate where the file will be saved (such as the Desktop or other easily accessible location) and then click on the "Save" button.
What is DxDiag?
A DxDiag is a utility designed to display the specifications of your computer hardware, as well as to test DirectX software, including sound and video. If you are asked for this information, it helps the support group relate your gaming issue to your personal computer.