Search youtube for Razr repairs.
You can get spare parts from your old razr or ebay.
Get torx tool from Home Depot: Husky 8-In-1 Precision Screwdriver

Agree with post above. It might be either a dead backlight, and the way to find that out is to power the phone up outside in the sun light. If you can see the picture showing up, then it's the LCD screen.

If you don't see any picture, even with the sun against it, then it might be a broken LCD flex cable, the flex cable came loose off of either the LCD screen or the main control board.
Both would require you to tear the phone apart. There are instructions on the internet on how to disassemble the V3 RAZR.

But if you just bought it from eBay, I would check the listing again on eBay and make sure that it said that the phone is in working order. If the auction you won states that the phone works fine, then you can file a "not as described" complaint with eBay / PayPal (assuming you paid for it using PayPal) and possibly get your money back.

I've torn a huge amount of RAZR's apart. They aren't hard to take apart, just need the right tools (mainly a torx t6, and a very small flat head screw driver).

It sounds like the backlight for the screen is dead. You need a new screen.

i got my razr off ebay for 50 dollars since my last razr broke and i have no money for a new phone. the screen stays black and when i push the power key the keypad lights up and a couple seconds later stops glowing. meanwhile the screen stays black and never turns on except for a couple times it turned white and when i pushed the power key it went back to black. someone pleasee help me. and i need a recommendation for a good phone that will last with minimal problems and isn't too expensive.