Here are the specifications from Excel 2010. There are others for older
versions of Excel so you may need to do a search specific to your
application.
http://office.microsoft.com/en-us/excel-help/excel-specifications-and-limits-HP010342495.aspx?CTT=5&origin=HP005199291
You should be OK looking at these specs.
However, in my experience Excel is a resource hog and this doesn't rule
out a bug in Excel or Windows 7. Make sure you have all the latest
service packs and updates loaded on your machine for Excel *and* Windows
7. Windows 7 is still a bit new and may be still a little unstable.
HTH
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