MacBook will only boot up to a blank screen

I have an old black MacBook (model A1181) that has been rock solid for the past eight years up until last week. My computer locked up, so I did a hard restart, it then booted up to a grey screen with a file and question mark. So I attempted to reset the PRAM without success and then I attempted to boot it up from the original install disc but it stopped even booting to the grey screen and was just a blank screen. A few years ago I doubled the RAM, so in an attempt to rule out the RAM i put the originals back in, but no luck still just a blank screen and I can hear what I believe in the disc drive engaging. So, after some forum surfing I thought I may have been the hard drive. I order a new drive http://www.newegg.com/Product/Product.aspx?Item=N82E16822136279 and installed it but it is still a no go, just the blank screen. Ultimately I don't care about the data loss I just want the computer back up and running, if you have any ideas let me know.