oops, i'm very sorry for my mistake, i do post on gentoo-user-fr in french, but I think I've clicked gentoo-user instead of gentoo-user-fr, sorry again.
So my problem is quite OT I think, but here is it : Since I've updated libpng AND/OR I've unchecked then checked the "smooth fonts" box in the KDE conf center, all the program which depend on KDE lags when I scroll the pages : quanta, konsole, Kate... Since there, the option was checked and in the advanced properties, the RGB subpixel and hinting too. Now, I must unchecked the RGB subpixel for not laging... I've a Athlon XP Barton 3000+ and a 6600GT with the stable nvidia-drivers. The other problem is when I click on Konsole or write it in an aterm as a user, it always opens a superuser-Konsole... My poor experience says to me : - a prelink problem ? (I've not yet prelinked KDE 3.5.5 as the 3.5.2 was) - should I reset the configuration of KDE by deleting files where it's stored (but I don't know where) ? - xorg problem, bad configuration ? (It was working since then) Could do push me to the right direction to correct this ? many thx nico.