I guess I download a virus altcoin wallet and the hacker found my private key in my desktop
It is quite unfortunate mate but there is nothing you can do to regain your assets. I advice u should be more careful what u download on line im the future so as to prevent this from happening again..Always use recommended wallets also to avoid looses like this in the future.
After downloading the crypto wallet from the untested websites, checking the malware with different virus-checking software can save the cryptocurrencies. The safety comes first, the experienced traders understand this but only inexperienced people keep ignoring this, unfortunately. The more we don't educate the people, the more people will be a victim of the hackers. Recommended wallets can be found after making a short search with search engines, lazy people don't like to waste their time with this nonsense.