The directory where MusiCAD was installed to (default C:\Program Files\Musys Software\) contains a removal program unins000.exe
The removal program will ask for confirmation before actually deinstall MusiCAD from your computer (Windows UAC will also ask confirmation on Vista and Windows7).
The usual way of deinstallation is by means of the standard windows installation/deinstallation program to be found in windows configuration screen, just like most other programs jou wish te remove wich will call the removal program above.
Please see http://support.microsoft.com/kb/307895 for detailed information.
Simply removing the MusiCAD directory and icons will not do much harm, but will leave some clutter.