Yesterday I almost cried when my PC didn't restart properly. As you know I already had to do a fallback because of service pack 1.
I only rebooted the PC normally, but when it tried to restart, it stopped at a blank screen with the underscore cursor blinking, nothing else. Tried to reboot again, but the same.
Strangely while booting up, I didn't hear any HDD spinning, so I thought that might be an issue. So I entered BIOS, but saw that it was booting correctly from the HDD and not any other device.
Saved and rebooted again, same thing. So I opened the PC and checked my cables, not that one of them came loose, but everything looked just fine.
So I booted again into BIOS and checked my HDDs. I have 5 of them, and they are all the same, hence the name is the same for every HDD, and you don't see which one is which, a little bit annoying, but only when you have to fiddle around with them.
But I noticed that HDD 1 was set as HDD 4, and HDD 5 was set as HDD1, which I thought was a bit strange. I looked then further, and saw that the HDDs have in front of their name 2 letters, different ones. And the HDD which was booting at the moment had PS, and the before mentioned now 4th HDD had PM. So that left me with the strong feeling that PS was standing for slave, and PM for master. So I put the PM HDD as the one to boot from, left BIOS, and look there, it booted again normally.
The only thing that I'm still asking myself is, how the heck could this change without touching anything BIOS wise or even in Windows?? The only thing I did was adding a NAS to my system, as I bought one for my movies and series to use with my new media player. And as the software didn't work correctly, I rebooted.
Have no idea what could have been the problem.