I have an hp pavilion it keeps shutting on and off... I did reseat the ram cards and came on and booted up... then next time it went back to its on and off deal.. Tried reseating, doesn't help any suggestions?

Could be a simple thermal shutdown.
When was the last time you blew out the vents for dust and other crud?

How far into the boot process does it get ?

Ok I found your answers but not how to respond... so I guess I will do it here... I tried everything, cleaning vents etc. I did get it to boot up once when I removed and reseated the ram cards, Now it just turns on and off... I even tried powering down etc. It is a used laptop and I do know that the motherboard was recently replaced. Got it from a friend who gave up on it... I haven't given up yet.. lol

No worries I've merged these together.
If you go towards the bottom of the page there's the answer box that can be used for responses.

Doesn't bode well if the mobo has been replaced.
Sounds like it's not even completing POST which is frequently terminal.

If you are feeling brave you could trying pulling the BIOS battery, BUT this means taking the whole thing apart, carefully.
At this stage you have nothing to loose and if properly organised it's quite straightforward.
The service manual is available online.

Hmmm I have pulled the manual and I am brave... LOL too brave for my own good, I did get it boot up great once, So I will try pulling bios battery. I take it this will reset everything to factory?

Well it's worth a go.
While you have it disassembled make sure everything is clean and plugged in correctly.

Hey, if nothing else, you'll have intimate knowledge of the internals of an HP machine ;)

OK thanks, wish me luck ;)

Best advice, be well organised and have coffee to hand..