You still don't say How or Where you were trying to restore this file, I ask because there is a specific means of doing this in avast, but a file should not be restored unless confirmed to be a bad detection. You also say it didn't work, why, what errors, etc. ?
If you have mover the file to the chest, the desktop short cut would be pointing at a non-existent file, so that should account for the (location error).
If you do as I suggest and upload the file to virustotal, you will have to jump through some hoops to avoid avast alerting as I have pointed out.
You can't get rid of an infected part as generally trojans can't be repaired as the whole file is malicious. Only true 'virus' infections can't be repaired and the Repair option would be available in the detection if it were.
Also the avast Win32:Trojan-gen is generic signature (the -gen at the end of the malware name), so that is trying to catch multiple variants of the same type of malware and is a fine balance between detecting a new variant and detecting something valid as infected. So I suspect that it may be a false positive, another reason why there is nothing to repair and the chief reason I ask you to confirm the detection (or otherwise) at virustotal.
So please follow the instruction in my first post, believe me it will be quicker in the long run.