Sorry, I meant "Isolated".
I believe what you have is called an "isolated" ground, not an
insulated one, which would make little sense. All that means is that
there are no other loads on that line sharing that ground. The theory
there is to offer some additional protection from ground induced
currents from other loads that might be present. From practical
experience of billions of users, it isn't needed for a PC.
So, yes you can extend it to another outlet using a normal
receptacle. Just be aware that if you put some nasty load on it,
like an AC, any noises, surges, etc will be on the same line as the PC.