hey guys,
thanks for you response!
yesterday evening i rebooted the n900 and everything was fine, realy strange. but i had a problem with the mediaplayer. he said: no connection with server while all my music was on the device( its about 2800music files). i rebooted again and everthing is fine. now when i use application manager the first time, its really fast. but when i use it the second time, i have got to wait for 15-20 minutes. realy strange...

But I'm happy with your comments!!

Thanks!