Question : Problem: Windows XP trying to upgrade 1g RAM to 2g RAM

Greetings.  
     Simply put I am trying to add two additional 512mb sticks of RAM to an ABIT UL8 motherboard.  I am running Windows XP.  I have several pairs of memory.  one pair PC3200, two pair PC2700(four sticks), and a pair of 266 at 256mb.  I have put any of the pairs in DIMM 0 and 1 with stable results.  The computer becomes unstable and will restart if I put pairs or singles in DIMM 3 and/or 4.  Occasionally the computer will not simply do a restart but will cause an error in a program which asks if I would like to send the issue to MS.  

   While I understand I might have four or so, bad chips, I find this difficult to accept given each of the pairs will operate the computer successfully if only DIMM 0, 1 are filled.

    Is there some setting I am missing?  
Thank you for your time.

Answer : Problem: Windows XP trying to upgrade 1g RAM to 2g RAM

From my experience I would say that it is a fault with the RAM Bus.  This is a problem with the motherboard.  If all pairs are working fine in dimm 0 and 1 but when adding a pair to dimm 2 and 3 cause errors in the operating system then there is a memory leak or something similar to that.  I would say stick with the ram you have or upgrade the first two slots.