點先知道自己部電腦係32定64位元?

PD930
http://indigo.intel.com/compare_cpu/showchart.aspx?mmID=878542&familyID=1&culture=en-US

P5LD2
http://hk.asus.com/products4.aspx?modelmenu=2&model=515&l1=3&l2=11&l3=185

你部機係可以行EM64T
Windows XP 係32bit定64bit, 你可以睇番system properties (控制台-系統)

for others
連粒U都唔知既話就用 CPU-Z check
http://www.cpuid.com/cpuz.php