Thanks for your suggestion genni. And thanks everyone who's replied so far.
I wish this tree had a second hole, but unfortunately it only comes with one. Although initially I said it was a seven and a half foot tree, when I looked again, I saw that it was a seven footer and the seven footers only come with that one screw and one hole.
I went to Walmart today and they were nice enough to open one of the boxes and let me see the directions.
Unfortunately, the directions for the stand were just pictures of it with an arrow pointing to the screw indicating how it goes in. I pretty much knew this already, so the directions were really no help at all.
The lady who worked there suggested hammering it in. I'm going to try that and if that doesn't work,I'm going to try and get an artificial tree stand. I saw some on sale online, but I'm afraid if I order now, it might get here too late, so I'm going to head to Home Depot or Lowes tomorrow to see if they have any. Wish me luck!