First of all, stop the forwarder so that it doesn't send more events.
Secondly, delete the events. Then, this answer might be of interest to you. http://splunk-base.splunk.com/answers/1630/how-do-i-delete-all-references-of-a-host-so-it-stops-show...
Please bare with me I'm a splunk rookie, I currently have a Windows server with a forwarder installed on it sending data to my spunk server, I just want to remove the server that is forwarding data to splunk from the host list in splunk itself, I wish there was a easy was to just hit delete etc in the host list, is there a specific cmd I need to run and if so how and from where? Thanks
It's hard to give a meaningful answer with so little detail in your question. Please take some time to describe your issue more accurately. What is the current situation, what is the desired situation?