Hey Pooka.
Got your package today, thanks!
Warming up the scanner now
For rar files you need something like 7 Zip which is an excellent (and free :) ) compression utility.
As for Excel...I read it you can view but want to edit, if that is indeed the case then I suggest you grab Open Office which is also free.
It does have some compatibility problems with microsoft's offerings, but usually only with the more esoteric formatting...