I want to add 2-3 addition fields for the searching contact in SearchUser.ascx.Currently user is filter by usernam which is display in drop down, In that drop down box I want to add field1 and field2 on that field  I want to customize the searching operation.For that I want to know two points of code,1. From where query is execute in code for ...

Daniel, If you are using II6, please set web garden setting to 1.  Please check this thread for details:  http://cutesoft.net/forums/thread/21301.aspx