Event ID 576/538 - Guest Logon

[carmen]

My system runs on windows XP Pro and today i have seen Event ID 576 and Event ID 538 in event viewer logs. They are as followed:

Event ID 576

Special privileges assigned to new logon:
User Name:
Domain:
Logon ID: (0x0,0x1EC738B8)
Privileges: SeChangeNotifyPrivilege

For more information, see Help and Support Center at
http://go.microsoft.com/fwlink/events.asp.

Event ID 538

User Logoff:
User Name: Guest
Domain: WORK
Logon ID: (0x0,0x1EC7356E)
Logon Type: 3

It seems as if some guest had tried hacking my system. In my case i don't use Peer to Peer file sharing programs and i have scan my system thoroughly and have found No infections by now. I want to know what these Event ID's means??? Has any one else came across it by now????

[unidentified]

According to the Event ID some guest has tried accessing your system and have tried messing up with privileges. I want to know if guests have to enter a password for accessing files or they can access it directly??? If not than assign password to guests for accessing your system and try disabling file sharing temporarily if you still see same Event ID's in event log.