I have an hp laptop and it's about 3 years old. When I power up the laptop it makes the sounds of booting up and the lights turn on but it just sits at a black screen with caps lock continually flashing. I have gotten it to boot up normally once by turning it on and off for a couple hours but then it went into sleep mode and now it back to not being able to do anything at a black screen with caps lock flashing. It has windows 7. Please if someone can help me that would be great!