Dell PC Screen Blank when I start up.

Hello,
I have had this Dell computer in my loft for a couple of years, it's only about 5 years old and hasn't been used much, so I decided to get it down and boot it up. It has always been fine with no problems, but after this long period of not being used the screen stays blank, the computer is booting up, lights are flickering, but the screen will not display anything. I have checked all the leads and everything looks OK. Very frustrating, as I can't even view anything to find out what the problem is. I want to give this computer to my daughter for her new flat, so If anyone has a clue what this might be please help.
Thanks
Brendan