It sounds to me as though you have had a bit of ‘finger trouble’ or you have ‘caught’ something nasty!
I’ll be optimistic and suggest you’ve been fiddling. Try this:
1. Go to the Windows Orb (Start), type Shell:Common Start Menu (note the spaces) and press Enter, now move the window to the left of the screen.
2. Go to the Windows Orb (Start), type Shell:Start Menu (note the space) and press Enter, move the window to the right side so that you have both windows alongside each other.
Click on the Programs > Accessories > System Tools folder in each window and drag shortcuts from the common start menu to your menu.