Yes, it could be the hard drive again...sometimes a machine that can't find a boot volume will present a solid white screen as you are seeing.

First, power on the machine while holding down the option key. If you get the option menu, then you know the issue is not with the screen. If you don't get the option menu, you may have a screen issue as Mayer suggests, but I bet you will.

If you do get the option menu, try booting up with your reinstall media, and install the OS over the top of the old one (without deleting the current volume) by choosing all the default selections. If the problem is that the operating system has become corrupted, this will replace all the necessary files, and hopefully you'll be able to boot again when it's done. If the hard drive is not visible when it asks where you want to install the OS, pull down the menu from the top and select Disk Utility, and see if it is visible there. If it is, you can format it, and proceed to install a fresh copy of the OS. If it isn't visible in Disk Utility, it likely has gone bad. At that point, I'd pull your hard drive out and re-seat it, just to see if that makes a difference, as sometimes they can come slightly loose.