Although Microsoft did buy the Giant Company and re-branded it's
Anti-spyware product into Microsoft Antispyware Beta1, that product was not
the Spam Inspector that Giant developed and sold before the acquisition as
a separate product. You can read a brief history of the acquisition here:
http://www.winsupersite.com/reviews/ms_antispyware_preview.asp
When Beta2 of Microsoft's antispyware was released, the code for that was
developed internally by Microsoft. It had no direct relationship to Giant
Antispyware let alone Spam Inspector, and it eventually was renamed
Windows®Defender. If you're still running Spam Inspector, I don't know of
any reason that it wouldn't continue to run along side of Defender (without
support, however.) But in any case, there should be no reason to
uninstall, and there is certainly no direct upgrade path from either of the
previous Giant products to today's Defender, it would be a separate
download and install.
