How to disable CTRL key interference on Windows?

Hey all,

Trying to do simple running control, forward/back/turning with WASD, holding SHIFT to sneak and CTRL to sprint. However, when holding down CTRL on my Windows 7 machine, it ONLY recognizes input from W, but not ASD.

If I hold down S first, then CTRL, it handles input from both. But once I let up on S and push again, it doesn't recognize it.

Any idea how to stop Windows from interfering with CTRL key on input?