#1. One of the problems occur with multiple instances is when you try to copy
formulas from one instance to the other instance. To each instance of excel,
they're just separate programs--so copying goes through the windows
clipboard--not excel's clipboard--and you'll find that things behave
differently.
#2. If you mean you can open a file by doubleclicking on it in windows
explorer, but the worksheet window is off the screen, you can use
window|arrange|tiled to see the worksheet window.
Then you can doubleclick on the worksheet window title bar to maximize it within
the excel application. Excel likes to help by remembering the arrangment of
windows -- You may have to do this (and then save the file) to stop excel from
helping the next time it opens the file.
#3. If you mean that when you double click on a file in windows explorer that
excel opens, but no workbook opens, then try these:
Tools|Options|General|Ignore other applications (uncheck it)
--- or ---
Close Excel and
Windows Start Button|Run
excel /unregserver
then
Windows Start Button|Run
excel /regserver
The /unregserver & /regserver stuff resets the windows registry to excel's
factory defaults.
Maybe one of these will work for you.