warning lights

Ok, 2 quick questions, my gf's 01 grand am SE just started giving her the change oil warning light today, sure enough I had been planning to change her oil anyways, so I did. I didn't change the filter. Well I just started driving it, and the light is still on, as well the seat belt light has come on, but I had the seat belt buckled. So I am going to disconnect the battery and reset the ECU after I finish typing this, I was just wondering what sensor I should be checking for the seat belt, and also what sets off the oil change warning light, a certain amount of miles in between filter changes??? Thanks

You have to manually turn off the oil light. It doesnt just come off by itself. Look in your manual on how to do it. About the seatbelt, i dont know. I disconnected mine, and my light comes and goes all the time. Not a big deal though. Also why didnt you change the filter when you changed the oil?

The filter was a bitch and not coming off, it was a premature oil change to begin with, so it really didn't NEED to come off this time, we were having a BBQ and it was getting dark and I was getting drunk and fedup (don't buy a 3 dollar oil filter wrench, you get what you pay for and it's was a POS) Anyway, I eventually quit after hurling the wrench as far as I could over my house. I would have checked the manual, but her car doesn't have one, she got it at a dealership used...
Also the seatbelt light went out after a few short drives last night, so I guess that was ok after all, I just wanted to know for future reference. So I am going to reset the ECU and see if that takes car of the oil change light...Thanks.

ok, i got it to work. you don't even need to disconnect the battery, after you get it serviced/do it yourself, just put the keys in the ignition, turn it to "ON" then depress the gas pedal all the way down 3 times, then turn the car on. The computer gets reset and the change oil light goes away. Any advice on the seat belt light would still be appreciated.

The instructions from my 2000 Grand Am owners manual (may be different for other years):

How to Reset the Change Oil Light

After changing the engine oil, the system must be reset. Wit hthe ignition key to ON (engine not running), push the RESET button located in the driver's side instrument panel fuse block. The CHANGE OIL light will start to flash, press and hold the RESET button again. The reset is complete when you hear the chimes and the CHANGE OIL light goes out

Yeah, I got rid of that light with the depreasing the gas pedal 3 times, I did some searching and found that online and it solved that problem.

But the seat belt light is on again. I buckle up, but the light stays on then flashes as I drive. Where are the sensors/fuses so I can figure out what is wrong with this. I don't have the manual. It's an 01 SE.