we have been running our oracle 9i rel 2 database installed on Win2k server supported by dual xeon processors for almost 4 months now. All was ok till yesterday.. suddenly the bulk inserts failed and thereon the oracle server hanged. we could not log into the oracle server from any of the client machines nor could we do it from the server itself. it simply hanged with no error messages of any kind. the CPU usage of the xeon database server showed 25% being still utilized by the oracle server. This is a very high use of CPU by any standards. Normally it takes hardly 10 -12% of CPU time. How can that be possible when none of the users are connected to the database? We have ran bulk inserts even before and never we faced this kind of problem. Finally we had to restart the database server and after doing that it seems its working fine. I have checked the alert log and the trace files but there also couldn't find any problem. Plz suggest me what could have gone wrong?? and how to find out what's wrong if the same thing reappears..