<<< Lan connection appears to be working ok but no internet on the client any more >>>
Does that mean that the two PCs are communicating and that File/Printer sharing is still working?
<<< When I try to look on host to see if ICS is enabled >>>
The Local Area Connection's icon should indicate whether or not it is shared - as with "shared" folders and printers, there will be a hand underneath it.
<<< ipconfig/all shows DHCP as not enabled if that is rellevant. >>>
The 'host' PC is given the fixed IP address 192.168.0.1 when ICS is enabled, so the details won't show DHCP enabled. However, at the top of the display, the 'host' should show "IP Routing enabled - Yes".
<<< The Windows Management Information (WMI) might be corrupted >>>
Check that the WMI service is running. Right click "My Computer" and select Manage. In the window that opens, click the [+] beside Services and Applications to expand it and then click on Services. In the right pane, scroll down to Windows Management Instrumentation, double click it and, in the box that opens, ensure that the service is running (Click "Start" if necessary) and that its Startup Type is set to Automatic.