I have used windows xp pro X64 but some of softwares are giving problems in it like office 2003 & other 32 bit based softwares. Now, I have formatted the system & installed Windows XP 32 bit but I feel the performance is reducing. In system properties with windows XP 32 bit, I am able to see only 4GB of RAM but my system configuration is of 16 GB. Whether windows Xp 32 bit is using full 16 GB of RAM or not, I doubt. Please help!
32 bit operating systems can only address 4 gb of ram. See this Microsoft Knowledge Base article for a comparison of 32 and 64 bit operating systems - http://support.microsoft.com/kb/294418