Sorry for the late reply. Interwebz issues.
You will not lose any information from an account that is removed from Outlook. Mail is stored in a PST file. You can back this information up using the import/export wizard. It is advised to do this periodically to ensure you have a comprehensive backup of your data.
http://support.microsoft.com/kb/270670
http://office.microsoft.com/en-us/ou...001103081.aspx
Removing an account only causes the system to stop checking that account during a send/receive. However, if you do not have an organized folder structure to your inbox (or other storage method), then you may have an issue where 293847923784 emails will be jumbled and difficult to locate. To create a folder, simply right click Inbox and select new folder. You can create folders within folders just as you do with data storage.