Most have 32 bit, though many systems now have 64 bit hardware. Even having
64 bit hardware does not necessarily mean that you are using the 64 bit
edition of WinXP. The problem is finding 3rd party drivers, they are often
not available for 64 bit systems. So if it's not supported directly by the
OS, it's useless. Unless you specifically know otherwise, chances are good
that you are using the 32 bit edition.