Assume they don't know anything about my password and seeds.If a hacker opens my windows account and copy the monero wallet folder,can they steal my monero coins?
Your wallet files are encrypted, so if you have a strong password - nobody can steal your funds by just getting the file, they'd need the password as well.
Further reading for wallet encryption:
Regarding theft in general, someone could steal your funds in few ways actually:
- Stealing your wallet file and password
- Stealing your wallet file and guessing the password (could work only if it's weak)
- Stealing your wallet's 25-word seed mnemonic. With the mnemonic, you yourself can also access your account from another computer or recover the wallet if you forget the password. Naturally, so can anyone else if he would obtain the seed somehow.
- Guessing your 25-word mnemonic. This is practically impossible if you generate wallet by random means (defaults). But if you picked your own words so it's easy to remember, you could be at risk. Note that with monero, it takes a rather long time to check if there's any balance so this attack is not practical. If the attacker knew your address, he could make guesses faster, but it would still be practically impossible to guess if it's truly random.
So, keep your files, passwords and seeds safe! And don't pick your own words unless you know what you're doing =)