How can I reset MacBook A1342, The old Admin's Account Password Prompt after Restarting the PC?

I bought a MacBook last week and went to reset it. When It turned back on, Its asking me for the Password for the account whose was on it. How can I reset it completely?

Okay so I bought this MacBook Model: A1342. It was working fine when I bought it and I decided to shut it down and restart it. When it turned back on, It asked me for (Admins Acct Name)

Password: ""

I Don't know the guys password and I have absolutely no way to get a hold of him. I've looked everywhere for this guy. I've given up hope. Is there anyway to get around this Prompt for the Old Admins Account, get on the Password Recovery Screen under the utilities page?

I've tried powering it off, Turned it back on and held Cmd + R keys until the apple logo pops up and loading symbol pops up. It loads and goes right back to the prompt for the Password of the Admins Account.

Ive also tried Command + S and nothing it doesn't power on, it just turns off and on and off and on. Repeat. Please help me!!!

MacBook(13-inch, Mid 2010)

Info:

Name:

MacBook(13-inch, Mid 2010)

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Processor and memory

• 2.4GHz Intel Core 2 Duo processor with 3MB on-chip shared L2 cache
• 1066MHz frontside bus
• 2GB (two 1GB SO-DIMMs) of 1066MHz DDR3 SDRAM; two SO-DIMM slots support up to 4GB