I’d delete the buddypress plugin folder, refresh your site to make sure it works properly and try a different way of uploading the bp plugin folder (if you did it through the Dashboard >> Plugins >> Add new, then try it manually or vice versa).
I did that already..didn’t work
is your theme built based on BP?!… if yes, rename its folder.
I use bp default. I rename the folder and now I got blank page.
reload your admin page: http://stecemu.weinandy.net/wp-admin/ and go change your details…
steps when uninstalling BP:
1- switch theme to WP default
2- deactivate all BP addons
3- deactivate BP
Thanks, it works !! 
does it means once I activate buddypress I can’t deactivate it?
the problem is when something related to BP is still active, it will call the engine whatsoever… if people do the uninstalling steps, properly, nothing is broken..
It would be cool to have a plugin where BuddyPress components/plugins are automatically deactivated when BuddyPress is deactivated and at the same time change theme to default theme (esp. with WP 3.0 2010 theme) so that there’ll be no more white screens of death. Something to think about.
for that, you need to suggest this in a ticket to the WordPress.org system…
You can actually switch themes on users under certain conditions via a plugin, so no, it’s not a core thing to go in WP.
Second, you can make the theme not error out when BP is turned off. Someone should run thru the code with some ifs and submit a patch.
when i suggest to post a ticket is relatively to the fact that if plugin X is deactivated, any related plugin is deactivated as well… this is a check that does not exists in WP yet, or it would ease a lot of debugs i can tell you… adding more if and asking people to check the code when they are not coders is not the good way to do things…
I’m not asking non-coders to do it, I’m suggesting ways in which coders can do it and submit patches so *everyone* can benefit.