|Orange light on what?|
If you mean on your monitor, and the computer is not booting, that indicates the monitor is getting no video from the computer.
The most frequent reason for no video is the computer's power supply is failing or has failed.
Sometimes while a power supply is failing the CD drive (and floppy drive) will not work because it is getting no 5v power from the power supply, or what was supposed to be 5v went too high and burned out the CD drive (or the floppy drive).
This computer model has a BESTEC power supply model.
200 watt power supply (HV, PFC, Bestec ATX-1956F)"
BESTEC power supplies are well known to be a lot more likely to fail than most power supplies, and if they fail completely - e.g. no leds light up on the computer case, the hard drive doesn't spin - they are a lot more likely to fry something else, often the motherboard.
I searched using: replace 0950-4107 power supply
Apparently your power supply is an oddball, smaller than standard, size
Dimensions: 100L x 150W x 86H mm (3.9" x 5.9" x 3.4")
An example replacent power supply:
Last one listed here:
(Note that HP makes both HP and more recent Compaq computers - the same power supply part number is also used in Compaq models)
Picture of replacement and specs:
This power supply has standard ATX wiring. BEFORE you buy a replacement power supply, if you can connect any ATX power supply from another computer to your computer, you can determine whether the BESTEC power supply failing fried the mboard - if connecting another PS allows your computer to work properly then there's nothing wrong with the mboard or anything else on the computer.
You don't have to install another power supply inside the computer case for testing purposes - you can just prop it up beiside your comouter case and connect the necessary wiring connectors to the mboard and drives.
For more info, look up the user manual for your model on the HP site