Need help formatting my comp!?!?!?

I just reformatted my computer and i don't know what's wrong with it. It's a pent 4 processor with the usual standard features, but when I reformatted it, things are a bit more weird. For example, it says I'm missing an hard drive? and the color is only 16 bit and the damn screen looks huge. There is no internet/local area connection. What happened? Before I reformatted it, everything was fine. The screen was small, color was great, and there was internet. I reformatted a different computer of mine, and it gave all the regualr features on that one. I did nothing different, but this one won't seem to be like the other ones. Also, when I reformat my computer, it usually says I have 30 days of free trial and then I must activate it. But, this computer didn't give me any option... Why? Why is this computer so damn different?