The oil pressure sensors on the Stilos are "PANTS", the oil pressure warning is a common problem, however i would still be extra careful, basically low oil pressure will not always be caused by Low oil levels, (If we accept the system sensors are working correctly!), so look out for any pump problems, any unusual noises etc.
If the pump isn;t ticking along nicely then the engine will not be ref the oil at teh correct pressure - hence an oil pressure warning.
Although my money is on the actual electronic system, .
Disconnect your battery for 30 mins to see if it will reset the lot for you

Right, well I took the car for its diagnostic test and nothing came up, but I suggested the battery. Turned out all the cells were down. One was at 50% and others at 75%. One new battery later and it's all fine now!

But here is a head scratcher for you (Or maybe not lol)... When I put the new battery in, I started up the car and noticed the mileage no longer flashed. YAY I thought, but when I turned it off and left it and then turned it back on for a test drive, it was flashing. I took the car for an hour or so drive and when I stopped and started the car again, it didn't flash... Thinking I might've found a way around it, I turned it off and on again and now it flashes again! Anyone got any ideas?

My friends Grande Punto is apparently doing the same thing but he hasn't added anything to the car? Would taking it to Fiat be worthwhile?