accesskey defaults

> When I make accesskeys for items on my page do I need to consider the
> accesskey defaults of each browsers' Menu items.  For instance IE for
> windows has F- file, E-edit, V-view, A-favorites, etc.  If I was to want
to
> use accesskey="a" on my page it seems to override my default.  I think
> overriding default ALT keys could render the browser inaccessible.
>
> I was hoping to use sequential accesskeys for my page to make it simple to
> navigate from one item to another.  I initially was using ABCDEF.  When
> doing
> so I rendered the Favorates, Edit and File menus inoperable on IE for
> windows.
>
> I ended up using 1-9 but obviously that gives me a very limited set for
> accesskeys.
>
> Is there a way a user is able to override the accesskey suggestion on the
> page or am I creating problems for my users.  Any suggestions?