There are several reasons why your elements may be hidden. You say they are on layer 1, so it's not a layer issue, but they could also be blanked. There are several commands that automatically blank entities.

Try this:

SAVE YOUR FILE

On you Keyboard, HIT Control-Shift and U (This is a shortcut for unblank all).

If that did not work, the entities may be hidden, look at your part navigator and see if you find a bunch of grayed out entities. If so, RMB on these and select show.

Hope one of these helps

Jim Rawlinson
Sr. Engineer CAD/PLM Support
Goodrich SIS California