1997 Lincoln Town Car Engine Light on

Computer problem
1997 Lincoln Town Car V8 Front Wheel Drive 101250 miles

Car runs smooth as anything, today had transmission flush and new fluid, new antifreeze, new oil, checked this and that. Still light on, no hesitation when starting, no loss of power going uphill, or idling, oh new spark plugs, no engine problem they said. I am 74 don't abuse car, am only driver and max speed at 60-65, no odor inside car, wassup? Need this to last me till I am pushing up the daisies. Am second owner, original owned autoparts store had to go into assisted living place. Am on very restricted income so don't want to take it to garage I don't know. Had the stuff done today at Sears. Manager said could not diagnose absolutely and could just be the computer sensor as car is over 10 years old.

Anyway since I wrote I took the car to Sears and had them flush the transmission and put new fluid - they told me that the engine light on didn't have anything to do with the engine - I had them drain and put all new fluids, just had silicone oil change Dec. They said it could be catalytic converter there are two on this car, however, it could be just a sensor, they didn't have the equipment to say definitely that it was the catalytic thing. Car is not smeelling at all, rides super, does not hesitate, doesn't lose power, starts right up, smooth as silk, so wonder the heck it is, got any other ideas, hope it isn't the catalytic thing 'cos that is going to break the bank for sure. I will make a donation but unfortunately cannot afford much just wrote out the bills, lol. Would $10 do it, if so let me know and I will take care of it.

updated 2-27-09
Hi,
Well regarding the "engine light on" bloomin' thing. So I took it to Sears - they said it was nothing to do with the engine - had the transmission flushed etc, figured that was due anyway - had the oil changed in Dec. 2008 do the silicone so that was good although they lost my dipstick and what's a gal supposed to do without a dipstick? - They drained and replaced the freezone (wrong spelling but you know the winter stuff, of course they told me it was black and when I had the oil changed I asked them to check and replace all the fluids? - Did it get black in 2 months? I only go 55 m.P.H and when I have a date(like never) I'll open her up and do 65 whooopeeee, I travel around town and two nights a week sing at a club (yeah can still hit the notes) about 20 miles from home off I95.

They said at Sears that it might be the catalytic converter, and I have two of them, well every gal should have two right? (I know I am being a silly old lady who feels like she is 47 instead of 74) However, she said she didn't have the equipment to really check that out and I should take it to the dealership.

Have any ideas? Oh car runs smooth as silk, no cutting out, no slowing down on hills etc. Starts up immediately no hesitation never have to restart. Starts up right away even in the coldest weather (no garage but vinyl soppy thing.