Try hooking a monitor up to your laptop. If that works, the display cable is probably defective. A replacement will probably run about $20 on eBay, which might be worth it if you know someone who is comfortable working on laptops or if you're comfortable doing it yourself.
If the laptop really isn't booting, you could try removing the RAM to see if it will at least beep errors at you when you turn it on.
If it still doesn't do anything, your motherboard has probably failed. It's possible to get a replacement, but it would be cheaper in terms of time and money to just replace the entire laptop. You can buy a portable external hard drive enclosure in order to recover any data, and if you have time, you could sell the working components (including structural components that aren't cracked) on eBay.
If you decide to take it to a local computer shop for a more conclusive diagnosis, but keep in mind that you can get a refurbished laptop with comparable specs for $200 or less.