Elementary OS is good one and lightweight also. Its based on Ubuntu, but optimized for better performance. I was also an XP user. Now I am using it as my daily driver for the last one and a half year almost and very much happy with it
Yeah tried installing, If I remember correctly, because of not having minimum required resolution some of the features didnt work. Havent tried again. Now installed win10 tech preview, but it is also a bit laggy. WinXp works really fast on my netbook, so looking for similar performance with linux.For atom processors 64bit will not improve performance . Have you tried Windows 8.1 32 bit? If not then give it a try, one of my friend use it on his intel atom and it works well for him
just look out for the dust clogged in cpu vents. you can use a air blower/vacuum cleaner for clearing the vents. use it to BLOW air in the vent through which cpu fan air comes OUT.I do clean it regularly. I change the thermal paste on my desktop PC from time to time, not sure if I should do the same for laptop. Any suggestions?