Nook color shutting off?

i got my nook color about 2 months ago (b4 the 1.2 update) and it wrked perfectly fine. but ever since the update its been acting weird. i have a subscription to cosmo and every time i try to open a mag my nook goes blank, like goes to sleep or something. i have to press the power button to turn it back on but then for like a second the mag shows and it goes black again. i have to press the power button and then quickly press the home button b4 the screen goes black. ive tried restarting it over and over again, turning off the wifi and turning it on again. nothing wrks. its frustrating me so much! i paid a lot for it and now its not wrking. im about to just return it, if i can. i bought it from best buy. is anyone else having this prob? does anyone know how to fix it? pls help!!