Hello fbsduser,
Windows se7en and 2008 R2 are for tests only and I've found a solution by using a 60 GB (external Hard Drive) for OpenBSD 4.5. Now /usr has a comfortable space of 38 GB and I am more quiet with the new space. Otherwise, thanks for your advice.
An other question : have you try KDE 4.X with OpenBSD ? What is the result ? Reliability ?
http://kde.org/announcements/announce-4.3-beta1.php
http://kde.org/info/4.2.85.php#binary
Thanks.
Valorisa