I have a 28.5 GB .tgz file which was created on the command line of a Linux computer, compressing one folder and all its many many subfolders. I now want to extract a single sub-sub folder from that .tgz file, using 7zip on Windows Vista. I can't see a way to do it.

Opening the .tgz file in 7zip just shows the .tar file inside it. There doesn't seem to be any way to browse that .tar file and extract the section I want. I assume there is a way to do this, but I can't see it.

Simply double-clicking on the .tar file brings up a progress bar which runs slowly till my computer complains it's running out of space; I imagine it's trying to extract the whole thing.

Searching for "extract section of tgz" and "extract tgz subfolder" and similar found me a way to do it on the Linux command line, but no obvious way to do it on Windows. (Most results found were about extracting into a subfolder, not extracting a subfolder out of the archive.)