Ok to answer the OPs question.
Ofcourse you can make your website available. But here are some things you can start on learning "how to use your computer as server for your website"
First, you must know that one "connect" to your computer using your IP address. (actually there's some port you must consider) Example. try typing "ping google.com" on your command prompt. From there you can see Google.com's IP address, copy pasting those IP address to your browser would also connect you to Google.com. Awesome isn't it?
Second, knowing the first, you must know if the IP of you internet connection is static or dynamic, how would they access your "computer-website" if you keep changing your IP? There's no worries, if your IP is dynamic, fortunately, there's a tool that will make your IP static. Cool isn't it?
Third, now we just need something to keep your server alive, I'm not gonna explain it now. But it comes as DNS.
All of those you can learn if you just Google it, but honestly, you won't get the answers here at the forum.
And you can do all of that for free. For those tool try checking any of the following services: no-ip, freedns, dyndns, etc.