craftgrrl | Sewing Machine HELP, please

I have a Singer Merrit that my Grams gave me right before she died. Well now I can't get the dang thing to work right and there's no instruction manual. Aperantly I can buy one for 15 bucks plus shipping but I'd really rather not have to do that.

Question #1: How old do you think it is?

Let me know if I'm right:
#1: thing to adjust the tension
#2: what kind of stitch
#3: where the needle is positioned
#5: length of stitched

That's are nice and easy to figure out but what the heck is #4?

Does the thread go in the notch in the front of the foot...

or in the hole in the middle of the foot that the needle goes through?

Why oh why is the it only working for one stich? No matter what I do it seems like it's working fine until I see that the bobbin thread and the top thread aren't actually, conecting/sewing/doing what they're suposed to.

And why do I keep ending up with all this extra thread? I thought it was because the tension was off but I adjusted that many times and it doesn't help.

I'm really hoping my machine isn't broken and I'm just having issues because I'm not used to this machine. I have a new machine that works fine and I don't have any issues using it, but I'm letting a friend borrow it for a couple weeks. Any advice would be greatly apreciated.