Sometimes, Windows 7 doesn´t complete start-up; the process stops at Intel DG43NB logo screen (the number 92 shows up inside a square in the lower right corner). When I press the restart button, most of the times it works, but sometimes it requires pressing that button twice. Once started. everything goes OK.
I have repaired Windows 7 and was told that something was fixed in the MBR, but fail persist. Then I run checkdisk, Western Digital Lifeguard Diagnostics (all mys disc are WD), Seatools for Windows, etc. and no problem was found.
Since I also have XP Professional installed in the same PC (a clone), I switched to XP and had no start-up problem at all.
I suspect that the Windows 7 related MBR is the guilty but I don't know what else to do to fix that.