Since safe mode still works, your problem is likely to be a corrupt driver
for some piece of hardware, such as the video or sound cards.
There are several possible solutions, short of reformatting.
1. Use driver rollback. This permits you to rollback the drivers for one
device at a time. It will only work if you have installed more than the
initial set of drivers. Otherwise, there will be nothing to roll back.
http://www.theeldergeek.com/repairing_windows_xp.htm
The above link als describes other repair/fix options. It is worth reading.
2. Try using an XP restore point from a time before the problem. This is a
low-probabilty fix, since restore points tend to fix corrupt registies, not
corrupt drivers. They can fix drivers if they were recently updated, since
an older restore point might also include the older (but still workable)
dirvers.
3. Try SFC. The XP feature checks ke system files against those on the XP
CDROM, and obtains a fresh vopy of any that are bad. But, to run it you
need an XP CDROM with the same level of service pack as the version of XP on
the PC. This probably will not fix a driver problem, but it can fix oter XP
problems.
http://support.microsoft.com/?kbid=310747
4. Try re-detecting hardware and hopefully XP will re-install the correct
drivers. MyCompueter, right-click, properties, harware, device manager,
highlight name of PC, actions, scan for new hardware.
5. Try using the device manager to uninstall a device, then to re-detect new
hardware.
6. Try to install drivers for all devices for which you have drivers on CD.
7. Try XP update and hope that it listed some newer devici drivers. If so,
intall them. These are not the so-called critical updates. Rather, they
are called optionl updates.
8. Try a "repair" install of XP. This refreshes all system files and
forces a re-examination of all hardware and nstalls appropriate drivers for
all. A repair is often used after changing a motherboard, but can be used
any time that XP get cirrupted and other fixes fail. Note that you need an
XP CDROM to do a repair. Further, some OEM CDs do not support the repair
option. If you did not install XP yourself, contact the PC maker for
advice. A repair "erases" all XP updates after the date of the CDROM.
Thus, after a repair install, you will need to run XP update, maybe many
times, to re-update XP.
http://www.michaelstevenstech.com/XPrepairinstall.htm
http://www.mytechsupport.ca/support/topic.asp?TOPIC_ID=2918
http://www.windowsreinstall.com/
http://www.help2go.com/article209.html