[I am running a script on a webbased application...so many use cases are there in my excel sheet....once the checking for the errors I have to go through next iteration...but sessionids are still present in the browser and disturbing entire process.. what can I do through script itself I am clearing temp internet files,deletecookies etc.. even though I am getting problem ]

To go to next iteration (login) you make sure you logout for the previous login....

Before login, use ClearCache () and see whether it works or not....