I have a 2003 Mazda MPV and this morning after starting my car I put it in Reverse and it wouldn't go. I put in in Drive and same problem. It shows on the dashboard that it is changing but the car won't budge..

Check the ATF level with the engine off. Then, check the level with the engine running--it should drop and remain in the safe zone. If the level remains high, the transmission pump may have failed or the transmission pump drive shaft may have strippped the splines in the torque converter (most likely). If this is the problem, install a Dacco torque converter, where they have beefed-up the splined drive washer (socket) to the drive shaft. They are available at AutoZone.

A less likely possibility is the neutral safety switch is bad.

Are you sure the emergency brake has released properly? With very cold, wet weather, the pads can freeze to the disc and the car won't move without some torque applied. Used to be a real issue with drum brakes

Does the shifter have a different feel than before? The cable may have disconnected from the shift linkage.