A desktop computer running Windows 7 32bit I started up recently immediately went into safe mode. I shut it back down and rebooted only to have it go right back into safe mode, with no warning or error messages.
After doing a bit of research, I found a couple potential issues and reasons why windows 7 starts in safe mode.
Network and Domain Issues
I wanted to try a couple of things before opening the case, the first thing was to unplug the network cable, since it was part of a domain. If there are issues with an ip address or the domain server is rejecting the computer for any reason, this can cause Windows to go into safe mode. Simply removing it from the network could eliminate any problems and boot normally. Unfortunately in this case, the computer still booted into safe mode.
After opening the case the first thing I tried was removing one of the ram sticks, after starting it up again the computer booted normally.
As I suspected earlier, there was a hardware issue, for some reason Windows was not able to give any reason for the safe mode boot. Usually I start by taking ram out, then the video card, any extra hard drives and cards such as nic cards. By process of elimination, we can determine what piece of hardware has failed.
The interesting thing was there was no post beeps or other errors, it could have been a loose seating for the ram stick, but i replaced it with a spare and now it is working properly.