Are these shortcuts that no longer work because the items they point to have been moved to a new location? If so, you can individually edit each shortcut to point to the new location. Just right-click the shortcut, select Properties, and then edit the Target field.
If you have a lot of shortcuts to fix, then you may want a tool that can do a search and replace on all your shortcuts at once. There is a "Shortcut Tool" that does just that within Right-Click Tools (a free tool package I wrote).