if it gave a blue screen error about the memory ..and just restarting itself ..its a memory dumping error and the way to fis it is to reinstall the operation system ...there really is nothing else you can do ..cause it just have problems with the physical memory ...so...
assuming that you never done this before I will place same instructions for this ....on how to boot from a cd and how to format C partition ..
remember that first you have to save all your importat data into the other partition ...and delete and rebuilt and install the C partition during the installation ....this will fix any hdd errors and get rid of any viruses that might be in the system ...( format in NTFS )
http://www.buildeasypc.com/sw/windows_xp.htmhere you will find the procedure for installing the xp into your computer ...remember ...there are steps that you will not need so ...just skip them
for example you will skip the 3rd party diver installation and wait for licence agreement ..
the only thing to be careful it the first part after the agreement ..it will detect your previous installation ...and show the C partition with windows in it ...here is the place where you delete the partition ....and continue with L to confirm .....after that will display the available space ...pres C to create enter to continue ...and format in NTFS ...after that the installation will load the files for installing ...and reboot and go with the devices and network ....
if you have a comon on board network card ...this will be installed by the xp automatically ...and you just have to configure it ...but if you have a separate card ...this will have to be installed after finnishing
this will be about all ...remember to have all drivers for all devices ...graphic card ...sound...and LAN ...the rest are pretty much loaded auto ..
for any thing that you do not understand ..just ask ...