Access my PC through the internet

"As others have stated, your router would have to be configured to forward the appropriate ports to the computer with the shares. You will be opening up a huge security hole, so consider other options.

Almost anything will be better than SMB/CIFS over the open internet. Personally I'd use SCP/SFTP to take advantage of SSH security. You could even tunnel SMB/CIFS over SSH... in theory. The only thing you'd need to do is 1) setup an SSH server on your computer, and 2) forward SSH ports from your router to the computer.

Now, to your question.

Your URI smb://dyndnsalias***/HostnameOfMyPC/Share won't work because you have two hostnames in there, dyndnsalias*** and HostnameOfMyPC. In theory (and depending on where you were trying to use this), the format would be:

smb://dyndnsalias***/Sharename
^ ^
| |
OR + host/ip + share
| |
V V
\\dyndnsalias***\Sharename

You can use any of these for the host/ip field:

your dyndnsalias*** alias (resolves to your public IP),
your public IP,
your HostnameOfMyPC, if and only if you've added it to your hosts file with your public IP (this would go in /etc/hosts on a Unix system, or C:\windows\system32\drivers\etc\hosts on Windows):

x.x.x.x HostnameOfMyPC"

"This is possible, but I would not recommend it at all as it can leave your machine open to attack.

I would personally look in to using something like either an FTP Server such as Filezilla or a HTTP Server such as IIS or Apache.

This will allow you to share the root of your hard drive or any folder and have authentication - along with being a lot safer."