Delete a user account or cross-site group

1. On the Web site you want to manage, click Site Settings.
2. On the Site Settings page, in the Administration section, click Manage Users.
3. On the Manage Users page, select the box next to the user or cross-site group you want to delete.
4. Click Remove Selected Users.
5. On the confirmation message that appears, click OK to remove the users.

1. On the top-level Web site, click Site Settings.
2. In the Administration section, click Go to Site Administration.
3. On the Top-Level Site Administration page, in the Site Collection Administration section, click View site collection user information.
4. Select the box next to the user you want to remove, and then click Remove Selected Users.

1. Click Start, point to All Programs, point to Administrative Tools, and then click SharePoint Central Administration.
2. On the SharePoint Central Administration page, in the Security section, click Manage Web site users.
3. On the Manage Web Site Users page, in the Site URL box, type the URL to the site, and then click View.
4. In the Enter Site User section, in the Account name box, type the user account you want to change or delete, and then click View.
5. To change site group membership, select the box next to the site group to which you want the user to belong, and then click Update.
6. To remove the user from all site groups, select the Delete this user account box, and then click Update.

You use the deleteuser operation to remove users from a site. The deleteuser operation takes the url and userlogin parameters. To remove a user, use the following syntax:

stsadm.exe -o deleteuser –url http://server_name/site_name 
–userlogin domain_name\user_name