These "network path was not found" types of problems are generally related to third party security suites. Either the installation or update / upgrade of such products can often times result in this issue, so...
I would start there. If you are using or have in the recent past used products such as Norton / Symantec, McAfee, AVG, etc., uninstall them using the control panel, programs and features applet and then Google for the vendor specific, proprietary removal tool and get rid of any and all remnants of said product.
Additionally it may sometimes be linked to credential corruption so check the credential manager on both machines and get rid of any credentials on either machine pointing to the other and attempt to connect again at...