XP hangs on startup; can restart in Safe Mode only

[Squished Ant]

After working normally for years, several weeks ago my system started hanging during XP startup. After the POST and related preliminaries, the XP progress bar screen (the little window under the XP logo with the moving dashes) hangs and stops responding about halfway through. There are no error messages. Nothing further happens, even after waiting a long time, until I hit the reset button. I can then run XP in Safe Mode which works normally except of course I can't use most of my peripherals.

I've tried all the suggestions and remedies, including reinstalling from the original XP disc, short of invoking a technician to find the cause and/or remedy this problem, and nothing has worked. Is there a clue as to what/where the problem might be, how I can track it down, or what I can do to fix it?

 

[CCT]

Just to clarify: After a clean install you still can't boot to XP normal? I mean, before you added anything else?

 

[Squished Ant]

I simply ran the XP disc thinking I could do a "repair" install, and it appeared to go through the entire install process. After that, there was no change in the computer's behavior. It still hangs about halfway through the Windows progress bar, and I have to hit the reset button to get a list of boot options, which gives me the option to run "safe mode". To my knowledge, "safe mode" is working normally, allowing me to do any work that doesn't depend on peripherals.