Aspire 1640

hello,my acer aspire 1640 has been booting up with a gray screen for 2 weeks now..i can boot it up normal if i keep shuting it off and on till it boots normally,but its a headache..i dont understnd it..i have went through 2 power outlets as well with this lap top in 1 year of having it..it will stay on all day once on and set to stay on ,and it will stay on in battery mode until the battery dies down then its back to off and booting ab normal again till i shut down and on again and again..please help me.thanku to all..