Unlike ActiveState, the magicsplat distribution does not associate .tcl
files with tclsh/wish. This is an explicit design choice for two
reasons. First, a .tcl file is more often than not a library or other
"helper" script, not the main application so associating all .tcl files
as applications did not seem right. Second, it is not clear whether .tcl
should be associated with tclsh or wish.
For these reasons, instead of associating .tcl, magicsplat associates
.tclapp and .tkapp respectively with tclsh and wish. Renaming your file
appropriately should work. If not make sure you selected the file
association checkbox during the install. You can also do so by running
the modify install option from the Windows control panel applet.
See the Shortcurs, paths and file associations section in
http://www.magicsplat.com/tcl-installer/index.html
On your Windows system, the Activestate uninstallation probably did not
remove the .tcl file association which is why it still works.
/Ashok