i also have the same problem with my css not viewing right in ie7 and firefox it is a real bummer as its my companies website and it views so badly my ownly advice is to regulary view the source code of sites that have a similar layout to your own i found this code and it fixed my text from over lapping in firefox but it still didnt centre align the whole page try it it my help.
a lot can depend on the software you use and if you use templates they can be a little buggy i found the best way id to learn css from scratch is the only way to get great results and cleaner code if however you do find the solution to the problem pleaseeeee tell me its driving me crazy.
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
"http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
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