check engine light

qhile driving, my check engine light came on i am at about 45,500 miles. i purchased my car about 1.5 years ago at 26k miles, and its been pretty good to me since. i have VERY limited knowledge on cars, so as soon as it came on, i pulled over less than 2 minutes later and checked the engine oil, trans and power steering fluids... about 15 minutes later when i got home, i checked out the bottom of the vehicle and noticed (what might have been there for a long time) a decent of gunky thick oil.. maybe its been there for a while? who knows.. i know that al vehicles after a while build up nasty stuff ander and all over, but maybe this is related to my problem? please hit me with your opinions..

The check engine light will come on for a variety of reasons. You need to have the codes read. Places like autozone will read them for free. Just call ahead and ask when is a good time to bring the car in.
After you have had the codes read, post the problem.