After the activity monitor is opened, the usereventagent does not respond, which may be caused by the software heart.
There is a hear under / library / audio / plug ins / Hal / Plugin is not compatible with leopard.
If you use leopard and have this problem, you can move the files mentioned above to a location. Of course, you’d better uninstall the software temporarily. The method is to open the heart, there is a uninstall under the heart menu, click OK, and then empty the wastebasket safely.
Now users should know how to repair the non response of usereventagent. Users who encounter this problem can use this method to repair it.