Trouble with Synthesia, your keyboard, or adapter? Think you found a bug?
When describing problems, always mention your OS and game version (shown at the bottom of the title screen).
If your keyboard has USB or MIDI ports, there is a tremendously high chance (>99%) it will work with Synthesia. See what you'll need on the keyboards page.
Hmm. Is anything else running in the background? (Chrome is actually a pretty nasty offender if you have several tabs open. Especially if there is video or Flash content in any of them.)
What are the specs for the machine you're running Synthesia on? Thanks!