Well, the hard-drive on my laptop died (it was displaying "SMART failure prediction -- Hard-disk Drive dailure might be imminant).
So I took it out and hooked it up to an external enclosure and copied all the files (system files and personal files, hidden and visible) off of it to another computer.
After that, I went and bought a new hard-drive. My previous hard-drive was a 250-GB 5400-RPM Western Digital. The new hard-drive is a 500-GB 7200-RPM Western Digital.
So I placed the new harddrive in the external enclosure and copied all the files I had copied off my dying harddrive on to it (my new harddrive). I placed it back into my laptop and booted it up.
I was expecting it to work when it said, "operating system not found". I rebooted again and brought up the Bootable-Devices menu and sure enough my new harddrive isn't even listed on there. Although, it doesn't detect it as a bootable device, the BIOS does detect the new harddrive (as I am running the BIOS' drive-diagnostics-program on it now which is almost complete). So I'm not sure what is going on.
I should mention that while backing up my files, I had no trouble getting all the files off my dying harddrive with the exception of a few (non-system) files associated with a Virtual Machine I had.
So I suppose my question is: Is it possible to boot from the new Harddrive? Or will I have to reinstall Windows 7 all over again?
Too long; Didn't Read...
I copied all my system-files (hidden and visible) from my old, dying hard-drive (250-GB 5400-RPM ) to a new harddrive (500-GB 7200-RPM). Is it possible to get Windows 7 to boot from the new harddrive?
I copied the contents of the old drive over to the new harddrive using CloneZilla and CloneZilla inidcated a successful process. I plugged the new hardrive into my laptop and I am still getting the "Operating System not found" error. Did I forget to do something? Do I have to fix the Master Boot Record or Boot Sector?
I have to thank everyone's answer to this question as they were all prompt, courteous, and informative. Thank you! I have solved this seemingly huge problem of mine and I will know how to do it in the future should it ever happen again! Not only is my operating system completely intact but because of your contributions and time, I did not have to resort to buying a copy of Windows 7 to reinstall it. Thank you very much! I am very grateful.