Why will a car not go into gears It starts but when you move the shift into a gear. The car does not move?

I am assuming this is an automatic transmission. The Transmission Fluid could be low, the filter could be plugged or your transmission could be cooked. Don't drive it, don't even try until a mechanic looks at it, could save you a thousand bucks (to replace the tranny) by letting a mechanic look at it first.

If it's a standard transmission, your clutch could be worn or burned out, or the clutch release bearing has failed, or your mechanical clutch linkage (if equipped) has become bound or disconnected, or the hydraulic clutch system (if equipped) is low on fluid or has failed somewhere.

Also there is a possibility that the differential is blown. Another possibility the e-brake is stuck on.