As a general rule, sliders are only nailed to the building through the outside nailing rail, and screwed to the header through the tract.
There should be some space between the top track and the header.
Cut an exploratory hole just above the top track and if there is a hollow, removing a 1/2" wide strip will afford you the space to raise the top track enough to complete the repairs.
You can patch the wall above the header or wrap it with moulding

Pull the jambs and track. That door will come out.

There are 4 screws, 1 on each corner for adjusting rollers. Lower top rollers and raise the bottom ones. Use 2 flat bars to lift bottom of door out first. If bottom rollers are shot you may have to lift the loose roller with a stiff putty knife while holding door up with flat bars. Needless to say an extra pair of hands will ease things considerably.

I think Klem1 has got it. Make sure the rollers are retracted top and bottom