HP DV200 Special Edition Laptop (Black screen, lights on)

Hello,

I have an hp dv200 special edition laptop. It was bought in 2007 so about 5-6 years old now. It works fine except sometimes when I leave it on and idle and I come back to it the screen is black, the lights are still on, but it will not respond or turn on when I press enter key or move the mouse. The only way I can get it to be on again is when I hold down the power button and turn it off and then turn it on. This has happened multiple times when left idle. I have also gotten the blue screen before but not as much. I am using Norton Antivirus 360 if that makes any difference. Any suggestions???

Thanks,
Liz
.