Hi Ron,
I have few ideas on what the box you see that is
preventing you from selecting a cell, I take it that the
the thing that looks like a text box doesn't have anything
in it; otherwise you would have told us what it says.
The closest is
a block of cells that appear to be selected and the "selection"
changes as you move the cursor (ghosting.txt on my site)
Perhaps you have turned on Cell Validation and don't have
a proper message, or protection turned on, but you should
get a message in the box that is doing the blocking.
For the other problem:
If you insert rows and then delete them you could have a last cell
problem, where Excel is keeping track of the high water mark
and increasing that each time you insert rows and not releasing
the last cell location when rows are deleted.
You can check this by using Ctrl+End, it should be the location
of the intersection of the last used row and the last used column.
If it is not then you have a last cell problem --
You can try resetting all of your worksheets with a macro ( all 4 of them).
Reset All Lastcells in the Active Workbook (#resetall)
Reset Last Used Cell ( see Reset_all_lastcells macro at...)
http://www.mvps.org/dmcritchie/excel/lastcell.html#resetall .
Then check your lastcell with Ctrl+End, if you still have a lastcell problem
then check out the MakeLastCell macro immediately have the
http://www.mvps.org/dmcritchie/excel/lastcell.html#makelastcell
If you don't have a last cell problem take a look at
Slow Response and Memory Problems
http://www.mvps.org/dmcritchie/excel/slowresp.htm