...bit type?How mant types in WIN XP SP2? My system is Intel P4 processor 541 with HT Technology includes Intel Extended Memory 64 technology(3.20Ghz,800Mhz FSB,1MB L2cache).The installed OS is Windows XP Professional SP2.One of a system analyser(Tuneup utilities 2007-System advisor)suggest me:Your computer has a 64 bit processor,but your current windows version only uses 32 of the available 64 bits.You should consider upgrading to windows XP Professional x64 to benefit from improved security and better ststem performance.How can I obtain such a OS and inform me the what to do.Please assist me.( a well experienced person with Windows OS.)