HP PAVILION dv7-6c66nr WINDOW SLOW AND WON'T OPEN TO MAIN SCREEN

I have had my hp laptop for over a year now, and this has never happened. You could turn the laptop on, but when it gets to users, and I press my guest (Forgot my password for administrator) it won't let me open up. And when it does, it gets extremely slow and won't open any icons, but just opens up a tab. Which states that you should end program or wait. I tried multiple times to push it on and th eresults would be the same. Except the laptop would linger on Windows for over 10 minutes. PLEASE HELP!! I WOULD LIKE TO KNOW IF I COULD KEEP MY DATA!! (EXTREMELY IMPORTANT FILES)