If your car begins to skid in bad weather,what should you do?

When your car goes into a skid, turn into the skid and pump the brakes (unless the vehicle has ABS brakes, in which case just hold the brake pedal down and let the computer do the pumping). Turning against a skid is likely to cause you to start a hard spin (3600 or more) which leads to total disorientation and often panic. Jamming your foot on the brakes can cause you to lose any friction you have with the ground rather than allowing partial braking. There are automotive schools that teach emergency procedures and these are very good places to hone your skills and become a safer driver.