problems with a 06 volvo s40?

[latasha]

first the check engine light came on then anti-skid then the transmission service light came on now it says that engine needs to be serviced urgent.also when i stop at a light and i start to press on the gas it acts like it doesnt want to pick up speed I took it to an mechanic and he said it was on o2 sensor. ok now I go out and try to start my car it want start it said something about the immobilazier start inhibitor. Can somone give me advice on this?