I've gotten a new computer (XP) and I am busy trying to reinstall all my mingw/msys stuff. I have an issue now with msys not being able to run shells as a background task. I used to be able to type tclsh& at the msys prompt and a new tcl shell window would pop up. Now I find that msys just crashes. If I type tclsh without the ampersand I used to get the shell started with the % prompt being shown. Now I do get into the shell, but I don't get the prompt. I have the exact same problem with cmd.exe.
Of note. If I type notepad, or notepad&, I get the correct response with a new window opening, and msys waiting for task completion or not as appropriate