If it's not getting to the point of booting from a device, then it's a hardware issue. Some thoughts:
* Unplug any USB devices, the hard drive, any additional sticks of RAM, pull out the battery, and remove the Wifi/Bluetooth etc cards and see if the problem still happens (if not, replace them one at a time until you find the culprit)
* Reset the BIOS. This step varies laptop to laptop. Google the instructions for yours.
* Is the CPU overheating? If the underside is extremely hot in one area this may be the case. Another tell-tale factor is if the laptop gets further in the boot process after it's been turned off for a long time (and therefore starts off cooler).
* Is the power cord connecting fine. I've seen laptops give these symptoms because of a dodgy DC jack. Even though the power cord is in its not charging, and if the battery is just about dead a few lights will flicker for a moment then turn off. (This doesn't sound like case here - it sounds like you get further than that).