Check your oven controls to make sure the controls are set to the right function and did not become loosened when you replaced the element. If you cleaned the knobs when you replaced the element, the knobs may have been put back on incorrectly. If you replaced an element inside the oven compartment and then used the self-cleaning cycle, make sure the oven door is in the unlock position before trying to use the oven.
It's possible that, in addition to replacing the element, you need to fix some oven power issues as well. If you unplugged your oven when fixing it, make sure it's plugged back in. If your oven has an electronic control system, then try disconnecting the power for about 30 seconds, then plugging the power back in. This resets the system and may solve your element issues.
Breakers and fuses control the electrical current flow into your GE oven. Check your breakers for the kitchen to make sure they're on. Sometimes when an element fails the fuse for your breaker is burned out. If the fuse has failed, you must replace it before your oven will work again.
If only the element you replaced is still not working, the problem may be the element connection itself, or the wiring leading to the element. The connection or the wiring may have failed or burnt out when your last element failed. Clean the element ports and examine the element setting for any signs of electrical damage. You may want to call in a professional for a closer look.