Code 00 can be caused by a few different things but is usually caused by a faulty motherboard, blown cpu or faulty psu.
A couple questions:
Did you have a working pc prior to code 00?
Did it still show code 00 when enabling the LN2 switch?
The first two things to try is clearing the cmos which you've done by removing the battery, next would be to try bios 2.
If you still have code 00, take everything out of the case and set the motherboard up on the box it came in with minimal components and see if you can get it to post.
If you still have code 00 then it's looking like a hardware problem with either the mobo, cpu or psu, it's likely will be the motherboard or cpu.
Give us an update when you get a chance.