While most cards do charge there are a few that don't. Check the card to see if there is a plug on it to accept power from one of your PCs power supplies. Some cards have this and don't draw from the PCI bus, but from this external power source.
If there is a plug there, just plug in a spare cord from your PCs power supply (if you have one left).
Otherwise, try switching the slot your card is in. Usually the first 2 slots are powered always. That might do the trick.
If that doesn't work, check the specs on your card to see if it's supposed to supply power..
And finally, get a different card if all else fails.