PostgreSQL. The platforms that had received explicit testing at the
time of release are listed in the installation instructions.
PostgreSQL also runs natively on Microsoft Windows NT-based operating
systems like Win2000 SP4, WinXP, and Win2003. A prepackaged installer
is available at http://pgfoundry.org/projects/pginstaller. MSDOS-based
versions of Windows (Win95, Win98, WinMe) can run PostgreSQL using
Cygwin.