Question time:
1 - How is your circuit built? Breadboard? or a proper PCB?
2 - How about decoupling capacitors. Do you have them 0.1uF across the supply rails?
3 - How are you powering the circuit? Chances are you have a bad ac adapter (assumption)

I know I'm asking the obvious, but, in times of stress, you need to recheck these.

regards
Jerson