MacBook will not boot up, screen is blank.

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. 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 Western Digital Scorpio Black WD2500BEKT 250GB 7200 RPM 16MB Cache 2.5" SATA 3.0Gb/s Internal Notebook Hard Drive -Bare Drive - Newegg.com 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.
MacBook, Mac OS X (10.4.11), Black MacBook

Either a logic board failure or, hopefully, a SATA cable replacement. They do become brittle with age and heat and when replacing the drive can crack.

Agree with Harry. Likely a bad SATA cable which is easy enough to replace. That particular series of MacBooks were fairly stable. It would be rare if the logic board gave out. Certainly a possibility, but I would do the cable swap first as that is not expensive.

Thanks for the quick replies, I appreciate it. Where do you recommend I buy a new SATA cable and what type would I need.

iFixit: The free repair manual

Mac Repair - Mac Parts and Service for Apple Macbook, iPhone, iPad

Have the model number of your MacBook on hand. The cables are specified by model number.

Try this:-

922-7579 Apple MacBook 13" Hard Drive (SATA Transfer) to Logic Board Connector Cable

Thank you very much guys, I replaced the hard drive and sata cable and the computer is running awesome. Thanks again.

Great. Glad to hear you're up and running again. Visit us often and have fun.