When I remove the caulk, does the windown come free or is it held on the inside by adhesive. What worries me is that a corner has started to pull away. Will adhesive caulk hold this corner from pulling free. What are the filled holes around window perimeter.
Yes, the window is held on the inside by adhesive. You can remove the window, but you must do so carefully, continuing to work a razor blade under the edge of the window to gradually un-glue it. If you attempt to pull it from one corner you will probably crack it.
The holes are screw holes. When the window was originally glued into place
( with, as Rick says, Dow 795) it was held in place by those screws, which were later removed and the holes filled.
Like Don, I watched the yard guys replace one of mine some years ago, then did one of my own 3 years ago. Be careful to remove ALL old sealant/adhesive AND be careful to tape and mask around the port both inside and outside when you rebed/reattach the port... Dow 795 can be really messy.