How to completely wipe an iPhone 4S?

Okay so I got this iPhone of eBay and who ever had it before me locked it with there iCloud so I restored the phone and now I need there iCloud stuff. Is there any way I could hock it up to my pc and just wipe it completely like it was never anybody's phone. Answer bellow or email me at surfingskyler@gmail.com please and thank you. Oh and I can't get in rich with the guy who sold it to me

Delete it

No not if its iOS 7, you need the password (be aware if its stolen even the find my iphone can't be turned off regardless, and will notify them where the phone is located anytime its on Wi-Fi or cell tower.)

Factory reset it. Plug it into iTunes on your computer go to summary and chose factory reset.

Reset it to factory settings

You can factory reset from the phone itself. With iOS 7, go to Settings->Reset->Erase All Content and Settings.

No. Unfortunately it sounds like the original owner accidently didn't properly wipe the device to prevent that from happening. You'd have to get into contact with him/her somehow.

There's no way around that.