Hi folks,
I recently transfered a high traffic website to it's database server to prevent high data transfers between web and SQL Server,
after I transfered the website successfully and changed DNSs and everything was working, I noticed that lsass.exe uses more than 50% of CPU.
When I stop IIS, usage of lsass.exe goes back to normal.
As I guessed it might be a user authenticating problem I changed the Internet Guest User to Administrator but it didn't work.

for the records:
server's processor is 2.8GHz and it has 2GB of RAM and it's running with 220MB of free physical memory
SQL Server 2005 uses 1,120 MB of memory

I appreciated your quick response.

please please please dont make the internet guest account an admin, undo that asap.


and you might have a virus, http://en.wikipedia.org/wiki/Sasser_worm


sc

the problem was with the connection string I was using to connect to SQL Server 2005.
I was using "Provider=SQLOLEDB; Data Source=localhost; Initial Catalog=TM;User Id= * ;Password= * ;" which works well with SQL Server 2000, but must be replaced by a special connection string for SQL Server 2005.
After replacing the old connection string with "Provider=SQLNCLI;Server=localhost;Database=TM;Uid= * ;Pwd= * ;" lsass.exe's activity went back to normal.

I hope it would be useful for you.

You might want to remove your passwords there!