Last night, not really willing to put in any more work, I decided to to give another go at installing Windows 7 on my main portable computer. I had already tried a couple of times with the Release Candidate, and tried once installing the final release on a different partition. So I was probably a little overconfident in letting it go to update Vista in my primary partition.
What happened is a sort of horror story. While in my previous attempts after the first part of the installation the sytem won't be able to boot the setup configuration, and I had to get back to Vista, eventually deleting the temporarily seup information and cleaning up the boot record, this time right after rebooting I saw the horrific:
A Disk Read Error Occurred. Press Cltr-Alt-Del to reboot.
At which you reboot and get the same error in a matter of seconds. Seeing no solution, I decided to bring the computer to the office, where I have setup disks and all. I was able to use Paragon Hard Disk Manager, which let me access to the disk, view files, check the disk status: everything seemd fine (and there was no apparent loss of data), but I could not boot.
So I put in the Vista setup DVD, opened the recovery console (after attemping the useless automatic recevery), and could access to the various system utilities. Did a check disk (chkdsk), tried to fix the check the BCD, the boot record configuration, with bcdedit, issued the various commands to the bootrec utility. All to no advantage.
I also removed my hard drive and plugged in an earlier (smaller) hard disk I had replaced in April, and it started fine, suggesting the disk controller and other hardware components were fine.
At once I go a low level file error (after stopping a chkdsk operation at half). So I run a low level disk check utility (the one coming with the disk and activated from the BIOS), checked multiple disk configuration in the BIOS itself (as recommended by many with the same error). Again, with no success.
After several hours (low level disk checks take quite some time!), I decided to "attack" the problem directly: I simply deleted the BCD configuration file and the boot loader. Now it booted like Windows XP used to do (probably using the older NT loader that was on the PC), I got a error of a missing boot.ini, and it didn't get through. But I could go back to the Vista DVD, let it fix errors automatically and rebuild a proper boot sequence, do a final chkdsk, and my system is back up and running. Odd, this solution was not mentioned in the dozens of site I looked for help.
It looks that my attend updated the boot record (BCD) but the problems was with the boot loader program, which was never changed. Deleting it, forced the repair utility to fix it!
Now it might as well be that the hard disk has some physical problems, but I consider the repair support of Vista too limited, replacing the three core startup files should be a standard procedure in my humble opinion. Anyway, all is well now.