there's nothing wrong with a sylvania, it seems like most universal remotes only work with the popular brands, BUT if sylvania is listed on the codes....i don't see why it shouldn't work.
i bet you i can figure out the problem(parents, teachers, friends always have a proglem between video settings and i always seem to figure it out).
If i were you i would go to BEST BUY/ CIRCUIT CITY/ FRYS and pick up a decent remote control(don't go for the cheapest brand/price this time). When you open it don't destroy the packaging, try and code it and see if it works.....if not just put it back and get a refund.
OOORRRRRRRR........let one of your homies or relatives and see if they can figure it out....