A problem with my brakes

[TdotAlero]

So I took my Alero out yesterday for the first time in over 2 months Nice weather so I cleaned her up, put my summer rims+tires on, all this crap. Was gonna go for a spin + get gas when a weird thing happened. Turns out I have like no brake power at all. I step on the brake pedal, there is pressure, but it's very hard to slow the car down. Now, the car was stored outside during winter, so the rotors got rusted. Also when I moved the car I heard a loud 'clank' from the brakes. My brake fluid is full (so no leak). Brake pads are new (maybe 2000kms on them). Rotors are not so good, but still fair condition. My question is could I have effed my master brake cylinder ?

[AlbinoMonkeyRat]

cylinder...probably not. it's plastic. my guess would go towards the system losing pressure from the change of seasons and not being used. Have you tried bleeding the brakes at all? make sure you have some back-up fluid just in case.