Try unplugging and reseating your RAM and vid card. Also, if you have two drives on the same IDE channel, check the jumpers on those drives to make sure you have no conflicts between them as Master and Slave. Cable Select doesn't always work well on all boards with all IDE drives so you may want to try hard setting the jumpers on the same IDE channel as Master and Slave.
If that doesn't fix it, try unplugging your hard drive and any other IDE drives (DVD, etc.) to see if your system is having trouble recognizing them or if they are conflicting. If that allows you to see a wake up screen, try running a finger across all the contacts on the drives before plugging them in again. I know that sounds weird. My theory is that it resets some stuck bit in the drive's electronics, but all I know is, I've done that several times on several systems in the past, and it worked.
If that doesn't fix it, try clearing the CMOS.
If that doesn't get it, you may have a bad motherboard or CPU. You'll need another CPU or another motherboard to test it to confirm if it's either of those.
Good luck.
