Assuming you're using a retail version of WinXP, you can try doing a repair of the os. Start up with the WinXP cd, after the drivers finish loading choose the option of installing Windows, accept the agreement, then on the following screen that shows the hard drive or partition that has Windows already installed on it press the r key on your keyboard and follow the on screen instructions.
For more detailed instructions/information you can go here: http://www.michaelstevenstech.com/XPrepairinstall.htm
I was installing some security updates yesterday off the microsoft website when I inadvertently installed a second copy of SP 2.
When I rebooted my computer it booted normally til it came to the desktop. Now it just cycles, that is the desktop blinks off in a couple of seconds then reboots again & again.
I can't go into safe mode or system restore. I can get into my bios or start up menu. I am pretty sure this happened due to the second copy of SP 2
Can you help me fix this thing?