I edited my previous post. An old email took me there instead of to the end here. The oil filter has to come off from the bottom. It is on the back of the motor, right next to the belt. As I mentioned in my edit, for whatever reason, if the oil filter decides to let go, it spews all over the belt, causing it to slip and track off. The pool of oil is usually half the size of the car before you can get it shut off.
Okay, I will embarrass myself and tell the story... I was changing oil and servicing my 93 late into the night for a trip. When I pulled the old filter off, I didn't see that the OLD rubber ring stuck to the assembly. So when I screwed the new one on, there were TWO rings and the pressure blew out between the 2 rings. I guess these things happen for a reason, like being able to share it with somebody that might have the same problem.
If you have not had the oil filter changed recently, it may have just come loose.
You will need to clean ALL the oil off the pulleys before you put a new belt on. Otherwise, you will have another ruined belt.
Don't you have a neighbor or friend that will loan you a jack and jack stand?
Oh, just remembered... use a "redneck creeper;" a big piece of cardboard!