This is exactly what has been happening when I start up my computer from a cold boot.
1. I see the Bios screen - Everything loads just a little slower. Like when it's locating the ram and drives, but it only takes about 10 seconds on the bios screen. Before this problem the bios screen would pretty much just flash on the screen for a second or two.
2. I see the words "loading operating system"
3. Black Screen of Death of 25-30 minutes
4. The Windows 7 Log-in page appears, so I log in and EVERYTHING is NORMAL.
The thing that puzzles me the most is that after everything loads the speed of all my applications and everything is just as fast as it was before the problem. So my main problem is the 25-30 minute hang-up with a black screen. I don't understand what could be causing this problem.
There are certain settings in the bios with regard to hard drives and that can cause the system to wait for eg. a raid array to initialize or you may have an anti virus proram that does a scan at boot up...
I would check those first but if you leave your system on 24/7 then I would not worry..cause it's better to be safe than sorry...
But still, I would look at those.
Sounds like a boot sector going bad. If you have a regular spinning drive, it will try to read the boot loader from the disk, if the disk is having read errors it will keep retrying until a max number of attempts occurs or it reads without a error on that block. Then it will try the next block and so on.
I would start by looking in my eventvwr.exe error logs from errors from a disk subsystem. Then I would verify my OS core files with
the sfc.exe /scannow command.
-I would backup my data on the assumption that the drive is about to fail.
-you could also run crystaldiskinfo.exe and look at the drives error counts(SMART data).
- maybe you have a boot sector virus that is to stupid to hide (run virus scan)
If it is a older spinning drive, the sector markers can become miss aligned as the bearing wear. basically the read/write heads will not be in the correct place over the platter at the correct time. The controller will attempt to fix this by attempting to move the head and read the data on the next rotation of the drive. It repeats this until it gets a correct read or gives up after some number of attempts. you can get this with a good bump to a drive or just with age of a drive. only way to fix is to write new sector markers with the repositioned head (basically, a full low level format or special software to pick up your data, write the sector markers and write your data back down on your drive.