Akash, dont even think about combining Apache on a Windows Platform, you'll end up in a disaster, even twice the hardware addition wont even bring you performance. Either go with Windows + IIS as web server, or Linux + Apache or nginx as web server. No Production server I ever experienced in my life at least with Windows + Apache combination.
If you plan to go Linux + Apache path, then there must be plenty on this community assisting you on that, if you're going Windows + IIS then most likely I'll be assisting, in that case, keep server O/S at least 2008 R2 or above as that came with FastCGI handling PHP making it perform way better on PHP based applications (Like Moodle, WordPress etc), I have a full tutorial uploaded on setting up Windows Server 2012 R2 with IIS to run Moodle, if you are going with Windows then i'll give you link to start yours.
Rest HD videos shouldn't be an issue, as I believe you'd be running them on local network.