Hi, I have an Acer Aspire 5552, recently when the cmputer is shut off it won't come back on? Everything is working except the screen, it comes up black? Every once in awhile if I let it sit it will come back on and work great until it is shut back off? I have tried holding down on the power button for 30 seconds with no power going to the computer. I have checked the ram's, I have pushed F2 and F12 and nothing. and I have tried to hook it to another monitor, it hasn't had a batery on it for 2 years because I have it plugged into power? I just don't understand why it will occasionally come on and work great until it is shut down, then right back to the black screen. Thank you, Lorri