I installed 0.9.2.1-win64, copied bootstrap.dat, allowed Bitcoin to catch mostly up (4 weeks behind current) and shut down Bitcoin. I copied an old wallet.dat to replace the existing wallet.dat. I started Bitcoin.
The bitcoin-qt icon appears in my system tray, and mousing over it shows tooltip text 'Bitcoin Client'. Left clicking on the systray icon does nothing. Right clicking on the systray icon does nothing. Doubleclicking on the systray icon does nothing. The GUI does not appear. The program's icon does not appear alongside the other open programs in my taskbar.
My task manager shows 851 Mb of memory use by bitcoin-qt.exe; and 5-10% CPU usage.
As I write this, my wallet FINALLY popped up with the correct information. I estimate the total time to load this wallet was 15-20 minutes on an i7, quad core 2.2GHz.
This is a really long time for a user to not know what's going on.