To me it sounds like you're either not letting it finish doing whatever it's doing at boot (I'd wait upto ~20 minutes for things like finalizing changes you made before your last reboot), or you have disk/file system corruption (probably in your registry). One guy stated that his motherboard broke his CPU and that's what caused it. Your computer wouldn't even load with a non working processor.
Like I said, unhook any newly attached hard drives.
In addition, either it has stopped booting into safe mode now, or it takes upwards of 2+ hours, and I haven't left it running for that long.
What's the longest you let it sit trying to load normally? Also, when going into safe mode, the last thing Windows lists (CLASSPNP.
SYS in this case) is the last thing it successfully loaded, so it's hanging on the 'next' thing (that it doesn't display).
You say you drives are OK, how did you establish this?
I personally prefer Hiren's Boot CD Here is the download page.
Boot from that CD and try running basic tests, like Memtest86+, which is for RAM, and MHDD, which is for hard drives and can detect bad sectors on your HDD. Do some preparatory research on the tool you are going to use, be as careful as possible.
Based on this, I would conclude the motherboard to be at fault. No matter how I set up the system, this seems to be there. EDIT 2: This is what it gets stuck at when I try to boot into safe mode: Note the slight graphical corruption at the top of the screen.