1. gave up CTP? well done!
2. create a major folder, like "scenario"
3. create a folder for each scenario in that major folder, like "lotr"
4. unzip the scenario zip file in that certain scenario folder
5. start civ2
6. "start scenario"
7. pick the location: open the "scenario" folder, then the certain scenario folder, like "lotr" or "wwi" or "jewels" or "mongol" or whatever
8. choose the SCN file from the file menu
this should work fine.. if it doesn't edit the labels.txt and increase the heap size... if that doesn't work: buy a new machine