thank you Dwayne ,
but nope. it didn't help.
at runtime it needs to compile every page - end even that takes very long.
and for you Micheal, it tried the INSTALL version of dnn , and at start I thought that the problem solved - but after another compilation of my code
(full rebuild solution) the slow behavior came back. i don't know why.
i tried even what you told me , and UNinstalled Team System and installed vs 2008 PROFESSIONAL - and the same thing - on 2.0 it running fast and when just
changing the website to 3.5 every page proccessing taking very long ( i looked on the ASP.NET TEMPORARY folder on the application and i see that it takes for some reason to output the compiled file very long time (while in 2.0 it just flashed out)
i think that (except of taking it as a bug ) maybe it related to the web.config somehow , i tried to look at the COMPILATION section and the differences between 2.0 and 3.5 and it seems that there are assemblies that are remain on both configuration (such as Visual basic ver 8.0.0.0 - is it ok? on v3.5 vb soppused to be 9.0.0.0 ???)
i tried the BATCH = FALSE and True - no change.
so now i'm looking for large application with a lot of assemblies to see how they compile and behave on runtime.
I don't know - maybe it because of My x64 bit or because of it's VISTA (one of the two or combination of both )
so do you see this behavior on yourself ? can you check the installment i pointed on my last post (with the large STORE module ) .
i'll try to run another large application (not DNN ) on .net 3.5 to see how it go and what configuration it has on web.config.
Do you know of a good web.config adjusted to .net 3.5 ? (DNN as it is , is for .net 2.0 and there is no .config file to 3.5 )
or maybe i'll give up and it's a bug that microsoft have to fix?
any further suggestions? 
thanks.
zahi.