clear combobox Items

dim strEmpty as string={}

combobox.datasource=strEmpty

combobox.databind()

Case sensitive search in SQL Server queries

Password Case Sensitive Search

Use COLLATE clause in your T-SQL statement.

SELECT * FROM dbo.TableName WHERE username=@username 

and Password = @ password COLLATE SQL_Latin1_General_CP1_CS_AS

Cannot use a leading .. to exit above the top directory

What this means is that your web page is referring to content which is in the folder one level up from your page, but your page is already in the website's root folder, so the relative path is invalid. Judging by your exception message it looks like an image control is causing the problem.

You must have something like:-

<asp:Image ImageUrl="..\foo.jpg" />

But since the page itself is in the root folder of the website, it cannot refer to content one level up, which is what the leading ..\ is doing.