Major Problem! Cannot start Plesk Web Interface!

[PraxitelisI]

Hello,

Please help me!! I have searched so many articles but didnt find the solution! What i did: updated MySQL from 5.0.45 to 5.5.28 . Everything worked fine. Then i changed the default "root" password (i didnt remember what was the last one) and i checked all websites using mysql (joomla, wordpress) were working smooth...

BUT when i tried to visit my plesk web interface i got this error!
NOTICE: I also realized when i run Plesk Parallels Panel -> Change on Programs and Features, the installer doesnt start at all! I get an error: cannot connect to database: access denied for user 'admin'@'localhost' (using password: NO)

What happened??? I am sure i didnt change the admin password! Is there any possibility that plesk 9.5.2 does not support mysql 5.5.28? PLZ help!!!

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The error i receive in Plesk Web Interface

ERROR: PleskMainDBException
DB query failed: Unknown error

0: common_func.php3:171
db_query(string 'set names utf8')
1: common_func.php3:626
reconnect()
2: common_func.php3:591
db_connect()
3: auth.php3:90