That machine would be fine for basic needs. I would assume (going out on a HUGE limb here....) that you have a server running 24/7? If so, install a virtual machine application (VirtualBox is free) and install it to that. Set it up with the absolute basics that give you a working network, take a snapshot, then have at it! You can't do any permanent damage at that point. As Pete said you don't need to know *nix as it is purely GUI driven.
I have my pfSense install running virtualized with 3 Intel GB NICs and a few VLANs so this "project" only increased my power consumption by 2 watts. I like running VMs because they are easy to backup, manage, and redeploy. Running a dedicated appliance, such as when I was using DD-WRT, would leave me with a HUGE networking mess to deal with if the hardware failed. In fact, as I was making the switch over my DD-WRT box started showing it's age and was dropping connections - after years of not a single issue.
Again, IPsec and PPTP aren't going to give you that freedom to use it anywhere on any network. IPsec is excellent for site-to-site 24/7 connections. That right there would rule them out for me, personally. If you decide to try out pfSense you can setup both OpenVPN and SSH within it - one piece of software to test out both of your needs.
Download the Live CD with Installer. You have the option of just running the live version on your old machine too:
https://www.pfsense.org/download/mirror.php?section=downloads
I have my pfSense install running virtualized with 3 Intel GB NICs and a few VLANs so this "project" only increased my power consumption by 2 watts. I like running VMs because they are easy to backup, manage, and redeploy. Running a dedicated appliance, such as when I was using DD-WRT, would leave me with a HUGE networking mess to deal with if the hardware failed. In fact, as I was making the switch over my DD-WRT box started showing it's age and was dropping connections - after years of not a single issue.
Again, IPsec and PPTP aren't going to give you that freedom to use it anywhere on any network. IPsec is excellent for site-to-site 24/7 connections. That right there would rule them out for me, personally. If you decide to try out pfSense you can setup both OpenVPN and SSH within it - one piece of software to test out both of your needs.
Download the Live CD with Installer. You have the option of just running the live version on your old machine too:
https://www.pfsense.org/download/mirror.php?section=downloads