Different versions of Excel? I know some things in 2007 run slower on faster
machines I have than same functions run in Excel 2003 on a slower machine.
There are some other things to look at - sometimes having tons of temporary
internet files will affect performance. Might go into Tools | Internet
options in your web browser (Internet Explorer) and clear out the temporary
internet files cache.
You also have to consider other possibilities such as either adware or
outright viral infections on the machine. I've seen good machines brought to
their knees through the loading of hundreds or literally thousands of adware
items brought into the machine through use of a variety of internet sites
(no, not just XXX sites). Each one fighting to get its ad products or
collect your browsing habits for future spam or whatever while you're trying
to actually get some work done.
Ad-Aware (a free version available from
http://www.lavasoftusa.com/ ) is
good at locating those kinds of things. A good anti-virus program can
usually identify most viral/worm infections on a system.
As a kind of side issue to Anti-virus programs: some are heavy on system use
and can slow performance also. Normally the 'hit' should only be about 10%
but some are much worse than that. For a good free one, I usually recommend
Alwill software's Avast! with Grisoft's AVG being another good
free-for-home-users package, and in the not-for-free arena, my first choice
is Kaspersky Anti-Virus, with Eset's NOD32 right beside it for those who want
a choice. Both of those are easily as effective as the "top 3" and actually
less prone to passing viruses/worms that actually go looking to see if you're
using one of those "top 3" sellers and have code specifically designed to
slip by them.