iPhone 4 stuck in recovery mode, iTunes error message pops up saying cannot be restored...how do I go about this?

Hi all..hoping someone can help me out with this.

So I recently lost my iPhone 5, therefore I am going to use a friend's old iPhone 4 in the meantime. The iPhone 4 has been jailbroken, but I wanted to do a reset to clear the jailbreak as well as just clear all other data, so that I can just restore my own iCloud backup & use with my own data.

However, the problem I am now faced with is that the phone is in recovery mode, and when I plug in the phone to my computer...I am given the options to click Restore. But after all the time it takes to update the software and supposedly doing its thing with "restoring" the phone....turns out no luck, i get an error message saying the phone cannot be restored. And now I pretty much can't do anything because I do not know how to do a reset of any sort to get out of this recovery mode.

PLEASE HELP. first time losing phone, first time trying to figure out how to reset and get out of recovery mode. I just want to be able to reset and then restore with previous backup..

I really appreciate the help. Thanks in advance.

*please ask any questions that you may need in order to help me solve this, since I am not exactly sure how to word some of these problems*