Is this the same non working PC ? If so, you forgot to close that thread.
Now, with the little info you provided, that it's an old PC. Could be a VIA KT 133 chipset based motherboard (this is an example) that had IRQ routing problems.
The points here are:
Determine your PC's configuration (you can use some third party freeware utilities).
Before installing SP2 (or starting fresh) you'll have to update the BIOS.
After you install the windows XP (SP2) you must also install the drivers (for motherboard and additional devices).
These being said, probable one of the drivers and/or startup applications are the culprit. For example, for the video part you can check if you can boot using "Enable VGA Mode". If you can boot there, the video part it's sorted as probable good.
One direction to follow for troubleshooting it's to simplify. For example, remove the unnecessary external devices and internal cards or integrated components (Example:disable sound in BIOS).
I think that's enough for the moment.
Trying to unweave, unwind, unravel
And piece together the past and the future,
T. S. Eliot
Running XP-PRO,750mHZ,AMD,512mb.I just did a clean install of XP-PRO and add SP-2 for the first time to my system. At my second boot up i was unable to get pass the running bars on my screen. After a few attempts i was up and running.It is now two days since and this time i cannot complete the bootup sequence unless i use safemode.The bars would scroll across the screen and then they begin to slow down until it just stops. anyone please help