Why i am not able to uninstall clam win Free antivirus software?

I don't know what problem you are having , but you can uninstall ClamWin via the usual Windows Start, Control Panel, Programs, click ClamWin. You can also uninstall it via Start, All Programs, ClamWin, Uninstall.

Also, perhaps you need to have administrative authority to uninstall it on your computer if you are not recognized as an administrator.

Regards,

Check whether your user is admin or not via start, control panel, user accounts and family safety then on user accounts. You'll be able to change your user status within there.