Someone hacked my PC, would they still have access on my files if I formatted my PC?

If they know your ip , then you are under trouble. Use a strong firewall and remove all sensitive infos from, you pc . Use a good antivirus ; to remove threats if you suspect that there is any on your pc. Good antivirus : AVAST FREE Good firewall : comodo

Dear friend, No, It can't access to it, but one thing you should format whole your hard disk drives.Before formatting take a back up of your all important files

after formatting your hard disk drive just all will be erased including hacker's software, so go to format your hdd.

actually all you need to do is start your windows firewall. Adjust settings to your preferences and feel more secure. You may also want to secure your router from intruders. Password protect it or even stop transmitting ssid thru router.

all information is destroyed when you format a pc. if your pc was compromised, you may need a better firewall or more hardened defenses with virus/spyware protection.