Your gloomy winter outlook may have been the fault of what you were looking out of -- dirty windows. Winter storms can leave a nasty residue all over that glass, much like the slushy, sludgy roads can make your tires look gross.
You'll want to tackle your screens first, in preparation for those perfect, sunny, breezy spring days that just call out for open windows. Take the screens off and take them outside for a gentle bath with a hose. If they're especially icky, you might want to rub them with some soapy water and a brush -- that old, dead fly is exactly the kind of depressing winter sight we're trying to get rid of.
Another tip: Start with the outside windows before taking the show inside, or you won't be able to tell whether they're actually clean or not.