Please help me out guys! no external screen and blinkin folder ? hdd is ok!

Try SMC and NVRAM resets:

https://support.apple.com/en-us/HT201295

https://support.apple.com/en-us/HT204063

If no success, make an appointment at an Apple store genius bar for a free evaluation.

Ciao.

If you attached a monitor to the MBP and there was no image, that indicates a GPU failure. There are no other software options available to try and correct the situation. You need to bring the MBP in for diagnosis and service.

Ciao.

When you have purchased or have been given a pre-owned Apple computer or an iDevice

there are some things a previous owner should do before giving or selling the unit to another.

• How to prepare your Mac for sale - the safe mac:

http://www.thesafemac.com/how-to-prepare-your-mac-for-sale/

Read through the following article and when you contact the previous owner ask that they

help you set up the product so you can take possession of it in the fullest sense of ownership.

Or see if you can get money back; more likely if you bought (used) from a legitimate business.

• What to do before selling or giving away your Mac - Apple Support

If you have one of these and the original purchaser has not released it from their accounts

and returned the computer to its original state so the next user can personalize it and make

full use of the features (including your own AppleID, App Store, iTunes, etc accounts) you

may find it won't work in some ways. Or it may work until you hope to do something, such as

update the software or upgrade to a newer OS X. Or buy & install apps from the App store.

About those iDevices: iPhone, iPad, iPod Touch. They also require extra special effort.

• What to do before selling or giving away your iPhone, iPad, or iPod touch - Apple Support

Had you mentioned early on that you bought a computer that still required a previous owner

or user admin and other details had not been removed from the computer to prepare it for

you to use, the other replies likely would have covered aspects of this topic, per links above.

To use disk tools from the recovery partition in the hard drive, there is a startup key sequence.

If you have somehow wiped the drive (in another enclosure or computer) the Recovery may be

erased. Some aspects of hard drive handling won't help re-set or de-personalize the Mac.

• OS X: About OS X Recovery - Apple Support

• Using Apple Hardware Test - Apple Support

• Apple OS X and Time Machine Tips:

http://pondini.org/OSX/Home.html

Good luck & happy computing! 🙂

The ?+blinking folder indicates that the Mac cannot find an OSX.

You can try two things: Boot the MBP with the COMMAND + OPTION + R keys. That should result in a display showing a revolving globe:

That will access the Apple servers and allow you to install the original OSX on the MBP. You will need a solid Internet connection.

If no success, the HDD may have failed and should be replaced. Then try the above again. Be advised I am not 100% certain that this will work.

Your best option still is an Apple store genius bar appointment. The evaluation will be free and they may be able to give you a definitive diagnosis of the problem(s).

Ciao,