At least I hadn't started my paper..
20 - 30 minuten
My laptop could not locate my hard drive software start up. It displayed the grey screen with the folder that had a question mark on it. My school tech bar tested both my HD and the cable for me. The HD worked perfectly and the cable worked with 1/4 of the test HDs, so they suggested I could take the risk and just buy a new HD cable.
I borrowed a friend's old laptop for a few days. I received my new HD cable from iFixit in 3 business days. My school tech bar installed it for me for free, which only took about 10-20mins. The start up is a bit slower than it used to be :( but it runs fine.
If you laptop can't find the startup software, don't panic. Your HD is probably still functioning, just buy a $50 new cable and you'll be fixed in no time. If you want, you can even buy the small screw driver and change the cable yourself!
In the meantime, if you need anything off your HD, bring it to a tech bar and ask them if they can hook up your HD like a USB on another computer so you can transfer some files to another USB.
*sorry don't have photos.... my cable is in my laptop now and I don't have a screwdriver to open it up again for y'all to see :P