My computer doesn't start properly it only starts in safe mode .it is happened after I run avast?

when you boot up it will say what windows you have and the other thing is this it will say system restore depending on if you have windows or what your running it will format the computer you need a copy of windows or installed windows meaning the product key is on the copy of windows or on the bottom of the laptop or pc then you need to have the key with you the computer will ask you for the key or you can go to control panel and do a restore that way to a earlier date just keep the windows key by you in case you need it