Hi s struble,
I too use XL on PC and Mac, but am having trouble understanding your
problem. XL always opens with the same numbers of rows and columns (256
and 65536 respectively). All you can do is hide them, but this won't
fix up the memory problem. My Mac is still only OS9 and I will get an
"out of memory" message, with even a reasonable sized XL file, if the
memory is set at the low level it has when first installed. If this is
the case with your Mac then you have to exit XL, select the XL icon on
your hard drive (not a short cut) then goto get infomemory and
increase the memory. If you're OSX then I'm not sure what the problem
is.

Ken Johnson