hi, since yesterday, (but yesterday isn't the first time this has happen) my computer everytime i try to turn it on, after it does all the windows screens when it should take me to my desktop, it takes me to either a black screen with large white pointer, or it will show my current wallpaper, but nothing else. i'm pretty sure it's a booting problem, but i'm not sure how to fix it. i had this computer built about three to four years ago. and i usually have no problems with it, except this one of course.