Sorry bout my late response but I use Windows so rarely these days that I forget these little things...
The start menu disappearing is an indication of the desktop going haywire, it happens quite a bit. The process that runs the desktop (start menu, window list, system tray, desktop icons etc) is called explorer.exe and it has a way of f. up quite often. What you do is the good old 3 finger salute (ctrl+alt+del) to bring up the task list. Then from the menu, choose "Run" and type explorer.exe.
For that matter, the next time your desktop is malfunctioning, do the same, kill explorer first and then restart it.
Finally, explorer.exe != Internet Explorer.