No. You can only upgrade from one LTS to the next or from the previous
regular version to the newer. You cannot skip versions unless it is from
previous LTS.

e.g. You can upgrade directly from 8.04 to 10.04 because both are LTS
releases and you can upgrade from 9.04 to 9.10, but not to 10.04.

Your best bet is to get a new CD and install from that. Since 7.04 is no
longer being supported and you did not seem to be worried about that, you
should wait an extras few weeks until 10.04 comes out and download or get
that CD. That way you can avoid having to install 9.10 (current CD) and then
upgrade to 10.04 LTS in April. That reduces your chances of having problems
by a factor of 2.