How to create a very simple server?

My home computer is NOT normally turned off at any time.

I'd like to create a very simple server on the computer so that I can access the files anywhere. And a friend of mine, only with username or passcode would be able to download files from the server.

1. How to create a very simple server for my need? Any freeware to do so?
2. Would running a server consume a lot of CPU usage?? I 'm worried about heat

 

Is your friend in your home on your network or in a remote location? If remote then you're also looking at router/firewall rules.

What operating system are you running? File sharing is available on pretty much any operating system out there, how it's done differs for each OS.

 

my friend is remote, even a little bit far away from me.

We are often sharing files, but we can only done through
service like cloud, and the upload/download speed is pretty slow, that's why I am thinking if creating a private server will help.

My system is windows 7, because I will clean re-install windows. I only have the license of windows 7, I don't know
if I will be advised to free upgrade to windows10

 

If your upload/download speed is slow that probably will not improve if you use your computer as a server. You will still be limited by your ISP.

 

Like TreeTops said, uploads speed on your connection and your friend's connection will quite likely limit you regardless. Much simpler, easier and safer to use a cloud base solution instead of opening ports on your router which could be exploited.

 

I agree. Cloud based is much easier and less a security risk than running a server on your family pc. Use something like dropbox, or google drive with shared folder.