Blank screen on cold boot for 5-25 minutes

For about a month or two my boot up time has gotten longer and longer, and my screen stays black throughout the entire process. You can hear Windows booting up and then after a minute or two I hear the entrance sounds, but blank screen remains for time periods listed above.

I have tried these steps to see if it was my monito, cabler or onboard graphics:

Changed from one HDMI cable to another...no change
Changed from HDMI to VGA cable...no change
Attempted a system restore to an earlier date and anything before a month it states file unavailable.
Attached an old monitor up...no change and then on the third day it turned horrible yellow tone.
Reattached this monitor, same experience with yellow.
Used both monitors and same VGA cable on old laptop and they worked beautifully without issue.
Opened up box to reassure all the cables were in solid and fans were working and all cards/ram seated well
Reconnected everything except my passport external (usb3 connection) Yellow discoloration seemed to have vanished on restart.

Next cold boot had the same issue and took 21 minutes for display to be visible.
Assured all drivers for mobo, video, monitor were the latest available.

Works normally after it finally boots up, but I have scoured the internet trying to figure out what could possibly be causing this. I checked for heat issues, but didn't find one. Today when I got all the updates from yesterday I restarted and everything worked perfectly (full screen with no blank spots and less than two minutes to boot). I turned off the computer for a couple hours, and on cold boot got the blank screen and it took about 6-7 minutes this time to be visible.

Any ideas out there as to what is going on?

Thanks,
LafnSu (well normally)

Thanks Britton for the reply, and yes, everything instantly comes up. I believe my friend may have a compatable gfx card, so I'll try it out. I'll also have to check and see if the warranty is up on the mobo as it was built last August. Let y'all know what happens.

Thanks again,
LafnSu

WOrk through these Troubleshooting Steps for Windows 7 to gather clues as something normally comes up.

Try updating the display driver starting with running all Important and Optional WIndow Updates, after enabling Automatically get recommended drivers and updates for your hardware (Step 3). If none appears then import the latest from the devices Support Downloads webpage. You can also try an older driver to compare.

Theres a trace that can be done which should reveal the cause by Gathering a Startup, Shutdown, Sleep, Hibernate, or Reboot Trace - Windows 7 Forums

Thank you all for the information. I am down with a flare from a chronic illness and thinking is marginalized. I'll try these items and post back soon as I'm up and around again. I really appreciate the responses.

Well, good news is I am much better, and I have been diligently going through the suggestions by GregRocker - about halfway through. There are errors in Event Viewer and I'm tracking them down....just slow. I really appreciate the help and will repost once I have (optimism is my forte) gone through everything and figured out the issue:) I will post log if not.

Thanks, LafnSu

Thanks everyone for all the help. It was indeed my onboard graphics. I've decided to disable it and replace with pcie video once I figure out what I need to buy that's compatible. After all the testing I shut the box down and then am totally unable to boot up so it took a bit to post

I sincerely thank everyone who posted as I learned a lot and all your help was awesome!

Thanks to all,
LafnSu