Urgent: IIS breaks

Hi, my IIS5 suddely broke, all websites can not be browsed. The log is excerpted
here:

#Fields: time c-ip cs-method cs-uri-stem sc-status 
08:27:42 172.18.18.77 GET /iisstart.asp 500
08:28:41 127.0.0.1 GET /DundasChartSamplesVS2005/ 302
#Software: Microsoft Internet Information Services 5.1
#Version: 1.0
#Date: 2008-02-27 08:29:11
#Fields: time c-ip cs-method cs-uri-stem sc-status 
08:29:11 172.18.18.77 GET /iwrok 404
08:29:16 172.18.18.77 GET /iisstart.asp 500
#Software: Microsoft Internet Information Services 5.1
#Version: 1.0
#Date: 2008-02-27 08:36:28
#Fields: time c-ip cs-method cs-uri-stem sc-status 
08:36:28 127.0.0.1 GET /SSOTestDnnSite_4_8/Default.aspx 500
08:36:54 127.0.0.1 GET /SSOTestDnnSite_4_8/Default.aspx 500
08:37:52 127.0.0.1 GET /iisstart.asp 500
08:37:59 127.0.0.1 GET /SSOTestDnnSite_4_8/ 302
08:37:59 127.0.0.1 GET /SSOTestDnnSite_4_8/Default.aspx 500

 What services are related to IIS? The only clue is after closing some services,
IIS cannot work.

Or any network setting I need to watch?

Thanks a lot for any help

Ricky.

IIS help is next door at www.iis.net.  Same login/password as here.  And look in
your event log, not the IIS log.

Jeff