Fixed some external links for Windows instructions

doc/install.txt

@@ -674,7 +674,7 @@ compile GotoBLAS2 (ATLAS may work too, but was not tested, and is
 usually reported to be slower and more difficult to compile -- especially
 on Windows).
 GotoBLAS2 can be downloaded
-`here <http://cms.tacc.utexas.edu/tacc-projects/gotoblas2/downloads/>`__
+`here <http://www.tacc.utexas.edu/tacc-projects/gotoblas2/downloads>`__
 (we tested v1.13).
 To compile it, you will also need MSYS and Perl (installation steps are
 described below).
@@ -689,10 +689,8 @@ installation.
 If instead you installed Python(x,y), you will need to install MSYS on
 top of the MinGW installation included within Python(x,y), as follows:
 
-- Download the mingw-get command-line installer binary from the
-  `MinGW files <http://sourceforge.net/projects/mingw/>`_ (click
-  "View all files", and make sure you do not mix it up with
-  mingw-get-inst).
+- Download the `mingw-get command-line installer binary
+  <http://sourceforge.net/projects/mingw/files/Automated%20MinGW%20Installer/mingw-get/>`_.
 
 - Unpack it into your ``pythonxy\mingw`` directory.