Due to age, changes in humidity, or improper installation, your carpet can break loose from its original adhesive and begin to wrinkle. The easiest way to fix wrinkled carpet is to rent a knee kicker (a common installation tool) and a power stretcher, which resembles a mop with teeth that you can adjust to the depth of your carpet's pile. Start by removing the carpet from the baseboard tack strip. Then, sink the teeth of the stretcher into the carpet's pile, and depress the lever of the tool to stretch out the wrinkle. When you've removed the kinks in the carpet, use the knee kicker to reattach the carpet to the baseboard tack strip.