First our website and its blog was hosted on a linux server and for some reasons we have taken this to windows server. After changing to windows server our wordpress blog is showing 404 error while changing the url structure. After searching for the solution came up with the suggestion to "enable and disable rewrite module at IIS SERVER". Once this is done our blog url's are static and working fine. But today noticed that category and tag urls are not working, showing 404 error. Could someone help me to sort out this issue?