Try to find an updated graphics driver for your computer.
Starting with the 10.3 update, Synthesia now requires graphics hardware that is capable of OpenGL 2.0, which became a standard in 2004 (and was widely supported by 2007).
We've described the reasons in more detail here, but the short answer is that despite our best efforts to maintain compatibility for as many users on older hardware for as long as possible, it becomes more challenging as that hardware grows beyond 10 years old.
If you receive an error about this while launching Synthesia, there is still a chance your hardware is actually compatible. We've heard from users running the generic Microsoft graphics driver instead of the "real" driver for their hardware. This seems to be most common on systems with integrated Intel graphics. Intel's driver page has a utility that can find the latest drivers for your system.
There is a special situation worth mentioning where upgrading to Windows 10 actually limits your graphics capabilities: Intel routinely stops supporting hardware after a certain number of years. So, 10 year old systems haven't had any driver updates since the release of Windows 10. This is troubling because Windows 10 requires new drivers made specifically for Windows 10. Because Intel doesn't provide updated drivers but Windows 10 requires an updated driver... you are stuck with the generic Microsoft driver. So, even though the hardware may support the OpenGL standard that Synthesia requires, Windows 10 doesn't know how to utilize it. This is a rather unfortunate situation and a fairly good reason not to attempt using the latest operating system on a very old machine.
In any event, if all else fails and you are stuck using a Windows computer that is incompatible with Synthesia 10.3 or later, the previous release should continue to work:
This forum post contains more discussion on the topic.