Bosses at Sony say more gamers have been hit by the same hackers who attacked the PlayStation network.
They said the latest attack targeted the Sony Online Entertainment (SOE) PC games network which hosts games played over the internet on PCs.
They think nearly 25 million people may have had their personal details stolen and the system's been shut down.
The PlayStation network closed on 20 April after hackers broke into the accounts of about 77 million users.
Users get an error message when they try to log on.
The hacking is worrying because information from the accounts could allow someone else to buy an item using a credit card, even though it's not their own.
Sony has promised it's doing all it can to fix the problems, but hasn't said when the systems will be back online.
It has said it has emailed everyone who's been affected with advice on what to do.
But if you get messages from anyone you don't recognise, don't open them and ask for help from an adult just to be safe.