Photoshop CS4 tryout - not working

I have previously tried Illustrator CS3, and I guess because of this I cannot install the Photoshop Extended CS4 Tryout? Have tried to use the CS3clean.exe facility, but this does not seem to do the job.

Am I "banned" because I tried out Illustrator without buying it? I actually intended to buy the Design Premium Suite next week, but now I am doubtfull. Will Adobe also block for the installation of this??

Please describe what happens.

Rob

Nothing! It goes through the install process and everything seems normal, but when everything has completed (no "success" message though), I cannot find Photoshop anywhere. No shortcut on the desktop, no program under "all programs", no folders containing CS4/Photoshop or the like under C:\programs\Adobe. So an install that ends up in nothing :(