WinSCP - No supported authentications methods available - Unable to use key file... (SSH-1 Private Key)
SSH-1 is obsolete for decades already. It's hardly ever used, maybe except for some legacy embedded devices. I'm quite sure that no AWS server supports that. And you cannot convert SSH-1 key to SSH-2. I cannot imagine, where you took the key from. In any case, you need to get a brand new key.