I received an old PC to use as a starting point for my toddler. The only upgrade I attempted was to increase RAM from 1gb to 2gb utilizing 2-1gb sticks(same mfg) DIMM 184pin unbuffered . After the install, I was shocked when the PC had problems booting up and when it did boot into XP Home, it kept rebooting automatically. It would take several attempts to get a stable OS.
Found out the sticks I purchased online from Koybe are crap. After some online research found out Koybe via eBay is a very unsavoury supplier. Re-installed the orig sticks of 512mb and PC works like a charm. If/when I decide to upgrade again, will buy from locale retailer. More $$ but less headaches.