from the Cygwin FAQ, it says that XP is supported. you might want to try downloading the latest cygwin DLL from http://cygwin.com/ and stick it in your windows/system directory to replace the one that came with pdp++. - Randy http://cygwin.com/faq/ That said, Cygwin can be expected to run on all modern 32 bit versions of Windows, except Windows CE. This includes Windows 95/98/ME/NT/2000/XP.