That's funny. I was under the impression that 64-bit processors (and by extension 64-bit OSes) were not available to the public until just last year.
Actually, since the first 64 bit processor was in 1961... and the first mainstream processors were released in I believe 92-93 (the Alpha Processor), followed up by the SPARC around '95. Now the first processor that MS Windows ran on was in 2001 w/ the Itanium, however they were expensive since there primarily server chips, so in reality your thinking of the AMD Athlon 64 which was released to the public in 2003, followed by the release of Windows XP x64 in 2005. So, just last year... No... 64 Processors & 64 Windows OS have been out for almost 3 years.