What is the problem with installing it? Do you have the disc? If so, insert it and it should start the installation process.
If you don't have the disc, you can download the trial version of the software thru the site linked below and then use your current serial number to activate it.
Be sure to follow the steps outlined in the Note: Very Important Instructions section on the download pages at this site or else the download will not work properly.
yes, there is but this link should make it more obvious for you.
if you follow all 7 steps, you can dl a trial via one of the links on this page: http://prodesigntools.com/download-adobe-cs4-and-cs3-free-trials-here.html
and activate with your serial number.
if you have a dl problem, you didn't follow all 7 steps. typically, failure to meticulously follow steps 1,2 and/or 3 is the problem.