CI********C13 is the serial no. Mac book pro. Blinking folder unable to connect the hard drive why?

They edited your serial number. That is not allowed under the terms of usage.

It will make it easier to help you w/ your problem to know know more information about your computer; size, exact year built, RAM installed and OS you're running. Any history prior to you incident would also be helpful.

That means that a valid startup disk can't be found.

A flashing question mark or globe appears when you start your Mac - Apple Support

Your startup disk could be corrupted, the disk failed, or poor connections

Reset the SMC and NVRAM

Intel-based Macs: Resetting the System Management Controller (SMC)

About NVRAM and PRAM

Try booting to Recovery and repairing the HD

OS X: About OS X Recovery - Apple Support

Next reinstall the OS if Disk Utility in Recovery can see the HD

OS X Yosemite: Reinstall OS X

If the HD can be found check the connection. Next replae tthe HD

Last:

Make an appointment at the Genius Bar of an Apple store.

Apple Retail Store - Genius Bar