To uninstall PSE11 follow the steps mentioned in the given link:- http://helpx.adobe.com/photoshop-elements/kb/uninstall-premiere-elements-photoshop-element s.html
And, for Lightroom follow steps in the given link: -http://helpx.adobe.com/lightroom/kb/manually-remove-lightroom.html
Let me know if further assiatance requires.
Thank you Sarika,
In fact, I'm afraid to have some problem to re-install pse 11 and lr4 on my new pc ... For example : "this program is also install on an other pc !"
For that, my subsidiary question is : Is -it necessary to insert teh Adobe's DVD before beginning the process on my Control Panel ? (to check that the program has been really uninstall from the previous pc).