Computer won't start after being put in new case!

[DresdenBBQ]

Howdy y'all! I'm in some desperate need of help here and I'm stumped. For four years now I've been working with this prebuilt PC I bought with the idea I was gonna eventually upgrade it. Got a graphics card only to find out it didn't fit in the case. So I just got around to buying a new case and a new 450 watt power supply. I had my friends walk me through setting it up, putting everything in, and when I turned to start it. It wouldn't start! I've been troubleshooting the problem for a day and a half now. I've tried not using the new power supply and tried my old one. Didn't work. Tried it without the graphics card. Didn't work. I've made sure the case fan is in, the graphics card and its power are in, the CPU power is plugged in, all of the case hookups are in, my harddrive isn't in but it shouldn't effect whether or not my computer starts. When I plug it in and switch the power on the fans will turn slightly in eight second intervals. So it's RECIEVING power, but it ain't on. It doesn't help that a manual just doesn't exist for the motherboard. So please!!! If anyone knows a thing i need the help. I'm willin to provide pictures if needed!

[TheOldMan]

Whenever that happens I suspect a standoff issue.  Just to make sure it still works OK, remove everything that is not absolutely needed.  If it still does not start, remove everything out of the case and lay it out on a piece of cardboard.  Lay the motherboard on the cardboard, then connect the power supply and keyboard and mouse.  If the motherboard has built-in graphics, try it without a graphics card.  Connect the monitor and then try to power up.  You might need to connect the start button from the case to the header, assuming you know where those leads need to go.  If you know the two header pins for the start button, it is not necessary even for that.  Just briefly connect the two pins and it should start.

Report back with results or questions.

[DresdenBBQ]

I'm not able to bread board it but since I had a prebuilt I put everything back into the original case and still no dice. No upgraded case, no upgraded power and no graphics. It won't start even with everything put how it was originally so the only thing I can think of is maybe it's somethin' to do with the CMOS-Password? When I originally took the motherboard out it had these blue caps with metal in them and I removed them without thinking. I've since put them back after realizin' they could be the problem but it still hasn't worked. Is there a certain way they should face/place I should put them???

[TheOldMan · Accepted solution]

Here is the support page for the motherboard.

https://support.hp.com/us-en/document/c04790427

Click on the "I/O Ports and Jumpers" topic. - last in the list - and then "Jumpers".  It will show those blue pins and the location for them.

[DresdenBBQ]

I managed to find a picture online of my motherboard and saw that I was completely missing a jumper in the ROM Recovery section, I managed to replace it and it booted up like a charm. I appreciate you going out of your way to help me buckaroo! It was mucho appreciated. 

[TheOldMan]

Glad to hear it is sorted out.