Dell inspiron 5110 .it boots..show dell loading screen..restarts

Hello,
my dell inspiron 5110 is having sme prblem....when the power button is pressed..the laptop starts and it shows the dell loading screen...after the loading...it shows a black screen with an underscore blinking...for a second or two...
then it restarts and...this continues like a loop...restarting unlimited times after showing the dell loading screen...
wat i can do with it?
somebody pleasee help me :(