1) send me a ticket to cyprus.
2) serve greek coffee and tiropitas
3) sit back and watch the pump magically get fixed
What chaz and Greg said are the most common problems.
First thing I always want to know: Is the problem in the pump, or somewhere else (like the water supply, regulator, air getting in.) If you're not experienced in figuring that out, easiest thing to do is to swap in a spare pump head, should take about 15 to 30 minutes to do that. If the problem goes away, repair the head. If not, your problem is somewhere else.
Also we can usually help more if you can attach a couple pictures of your pump setup.