Hello,
Thank you for posting your query on Microsoft Community.
As per description, you are getting error message "The remote computer was not found" while starting Task Scheduler.
I would suggest you to follow the methods given below and check if that helps.
Method 1:Perform Clean Boot.
Placing your system in Clean Boot state helps in identifying if any third party applications or startup items are causing the issue. Check this issue in clean boot state.
Refer: How to perform a clean boot in Windows
http://support.microsoft.com/kb/929135
Note: After clean boot troubleshooting step, follow the section "How to reset the computer to start as usual after troubleshooting with clean boot" in the provided link to return your computer to Normal startup mode.
If issue still persist try method 2.
Method 2: System File Checker.
You may run the system file checker tool and check if it helps. SFC scan will scan for the corrupted system files on the computer. You may refer to the following article in order to use System File Checker tool appropriately.
Use the System File Checker tool to repair missing or corrupted system files.
http://support.microsoft.com/kb/929833/en-us
Hope this information is helpful. Please do let us know if you need further assistance with Windows.