My Seagate Backup Plus Portable Drive Doesn't Show Up?

First and foremost I want to apologize in advance if this problem has been posted before. I was unable to find the help I needed. So Im posting this.

Today for some odd reason my Seagate Backup Plus Portable Drive does not appear at all on my Macbook pro. Its hooked up and theres obviously power to it cause the light is on the HDD. The Macbook had crashed previously and after rebooting the hard drive does not work. Can someone please assist me. I have all my media and personal document on that hard drive and I need it for college. I don't know what to do?

So when you say it doesn't show up does that include Disk Utility? If Disk Utility cant see it then you may have a serious problem.
You say your Mac crashed a few days ago. Was the portable HD connected at the time?
How did you repair your HD? Why did it crash? What symptoms did it display when it crashed?
What Mac Book Pro (year) are you using and what OSX are you running?
We need all this info before we can begin to help you.

Rod Sprague said:

So when you say it doesn't show up does that include Disk Utility? If Disk Utility cant see it then you may have a serious problem.
You say your Mac crashed a few days ago. Was the portable HD connected at the time?
How did you repair your HD? Why did it crash? What symptoms did it display when it crashed?
What Mac Book Pro (year) are you using and what OSX are you running?
We need all this info before we can begin to help you.

Click to expand...

Yes its not showing up in the Disk Utility
Yes the External HDD was connected when it crashed
I wasn't able to repair my HDD cause I cannot access it at all. Cause it doesn't come up.
I was moving some files from the Mac to the HDD then a ballon spinned and boom it crashed.
Macbook Pro (13-Inch, Mid 2012)
Processor 2.5GHz Intel Core i5
Operating System: OS X Yosemite version 10.10.2

I'm wondering if it was your Seagate external hard drive that caused your MacBook Pro to crash? If Disk Utility can not "see" the Seagate, it's going to be difficult to try to recover data from it. There are utilities which you can try using to access the Seagate, however, they're all very expensive and there is no guaranty that they will work.

It's possible your data is OK but the electronics on the Seagate have failed. In that situation, the enclosure can be removed to expose the bare drive. Attaching the bare drive with an adapter to your MacBook Pro may allow extracting the data from it. Of course the drive itself may be defective and that method would not work. Without a backup of your Seagate, it's up to you to what you're willing to do to get at your data.

DjChubbs, it doesn't sound good for your external HD as stated data retrieval software is expensive and no real guarantees if it will work until you try it, for example Disk Warrior. It is as chscag suggested entirely possible that the external HD was the cause of the crash in the first place.
Removing the storage unit and putting it in another enclosure might allow you to retrieve your data. Either way it is probably cheaper to take it to a service center where they can try a number of possible solutions. Is this portable HD the only copy of this data you have?