Help!!! Adobe photoshop cs4?

I just bought Adobe Photoshop cs4 and when i opened it, there was a message that says. "some text layers contain fonts that are missing. These layers will need to have missing fonts replaced before they can be used for vector based output" What does that mean? I went to adobe's sight and they did not help. they sent me to some article about another adobe program that is not photoshop and the articla was confusing and not very descriptive. Also whenever i try to use different tools like the paintbrush, gradient, or anything else it says "could not use this tool because the target layer is hidden". What? Does this mean that the fonts did not download? And whenever i try to save the file as anything but a psd file i can't. It blocks me from changing anything or clicking anything in the save options section. And a little yellow triangle pops next to the layers box and i can't click it. Also another yellow triangle is at the bottom that says "file must be saved as a copy with this selection". Ugh I'm confused and the last thing i want to do is pay again or something. Why is it acting like this? Also before I bought it I tried the trial version and some download manager from the adobe website starts downloading but never completes the download. All it does it say there is an error and when i try to resume the download it still gives me the error message. I've never downloaded the trial before so I don't see how it won't let me download it. Do you think i have a virus messing everything up or what? Because my computer and web browser has been freezing alot. Plz, help ifyou kno what i'm talking about. I really need this thing to work.