I've got a 2 or 3-year old desktop that was running Windows XP Pro.
It hadn't been used for a while, so I thought I'd update it to Windows 7 and get it running again. When I fired it up it went to a black screen after showing the Windows XP logo.
I thought the drive was corrupt, so I went ahead and put in the Windows 7 upgrade disk and rebooted. It started the install program, and went ahead normally. After installing, when it was time to reboot to finish the installation, the machine just kept rebooting itself, and going to the Windows boot selection screen (safe mode, safe mode w/ networking etc.).
If I choose safe mode, it won't complete the install process and forces a reboot. If I choose boot Windows normally, it just goes to a black screen and reboots itself again (and again, and again).
I tried the system repair several times, and it's pulled a couple different errors, one that said it was a bad driver, one that said it was a corrupt partition, neither one of which windows could fix.
I also tried check disk, but again, it went all the way through the check process and died on reboot.
I tried another install, this time using the advanced options and deleting the existing partitions and formatting the drive (though I can't believe it really formatted, since it only took a few seconds!) with the same results.
I'm at the end of my rope here -- what else could be causing the problem? I've tested the memory and it came out with no errors -- could it be motherboard or I/O issues?
Thanks to the commenters below, I tried a few more things.
At one point, the install process completed, and I was able to get up and running in Win7. The system downloaded about 150MB of updates, and requested a reboot. Once I rebooted, it was back to the same behavior-- after the Windows logo loaded, the system went black, and immediately rebooted.
I tried the tip to disable automatic reboot, but it made no difference-- it rebooted just the same. I tried all the options on the boot menu in fact, and nothing made any difference. It was just a hampster wheel of reboots, over and over. I tried booting into safe mode and it hung for a long time on the driver list, then rebooted.
I'm pretty sure it has to be hardware related at this point (motherboard maybe?) but I don't know the next things to try to narrow it down.