I have a fairly old Intel D975XBX2 based homebuild that's been working OK (Windows 7, 4GB RAM, ATI 3850 GPU) but lately is taking it's time starting up. I clock approx. 2 minutes before it even displays the Intel power-on (F2 for BIOS) screen. All that time the fans spin (full speed), drives are being "hit", and CD/DVD drive is flashing (try to read a disk). I disconnected all SATA devices but got similar slowness. This only happens when the box is COLD. If I reboot when it is warm the box fires right up.
Also, I thought it might be the battery (2032) so I replaced that. No change.
I would try defaulting your BIOS settings, as well as flashing the BIOS to the latest version. Do you have another video card to test in there, maybe onboard? I know I've seen a similar issue, but I can't remember what the issue was. Could really be quite a few things. Maybe PSU, CPU, or RAM problem, but hopefully not.
The problem has worsened, sometimes the PC won't boot at all. If it sits powered off for 5 - 8 minutes it will generally boot, but will only POST after about a 3 minute "warm up".
I spent last night trouble-shooting - literally pulling everything out replacing things one at a time (everything except CPU I should note...).
One thing to note: while the 3 minute delay in POSTing occurs, the red LED next to the CPU is flashing. Once it boots and loads Windows, that light stays off. I'm thinking it is undervolted, or not seated right.
I'm thinking my motherboard or CPU is going south.
One additional question (and I'll post this separately too...): If I replace the motherboard, CPU, RAM but keep everything else, will I need to fully re-install Windows 7? Or can the OS handle such a radical shift in HW?
Generally replacing motherboard for exact same model does not require a rebuild, replacing Mboard for a different one will need a re-install.
If boot time as you say is the same when you only have VGA,CPU and RAM installed then you can stop worrying (for the moment about HDD,etc.) Though I will say one thing, and this is VERY RARE. I once went to a repair where the computer took ages to boot up, turned out that the guy had installed a USB hub which seemed to be slowing down absolutely everything including boot times, removed it and it worked fine, try diff usb devices if using them.
As brandoncatz suggested, try your default bios settings. I cleaned out my PC of 7 months dust on Saturday and even though I put everything back exactly like I found it for some reason it wouldn't even give a post screen, or would stay on the post screen for a long time, reset to default upped the voltage for the ram I had in there and its a happy camper again...though why I didnt like the previous settings that it has been working PERFECTLY for 7 months I cant tell you.
I tore apart the entire machine part by part to try to localize the problem. I was really starting to fear the mobo was blown. But then I did some independent testing of the power supply and was suspicious enough to try another.
Replaced the 750W PSU with a new 600W and all is now well. Everything seems to be working just fine.
Thanks to all for the advice. I did find one thread where the guy said to ALWAYS swap out the PSU first... Next time...