Newbie question: missing codecs

[Aira]

Hi everyone! I need to make some clips and my new computer came with Adobe Elements 9, which I've never used (upgrading from CS2 on my old craptop). I have heard great things about Premiere as an editing tool, so I booted it up and was immediately disappointed by missing codec messages when I tried to import almost any of the video files on my computer.

All of the video files I have play just fine on Media Player Classic and VLC and can even be opened by other editing programs (but the programs themselves are not very good and I'd rather use Premiere). The files are all .avi and I have no idea what codec each of them uses. I know I can download codecs that are not yet installed, but I don't know which ones to look for. Also, why is the codec not found by Premiere while it works fine with other programs?

I would just download a codec pack, but I've heard that they can be dangerous for various reasons and I don't want to risk any problems on my new computer - it cost a month's salary!

Thanks a lot in advance for any advice, and please go easy on me as a newcomer to this type of video editing.

[Spacial]

With this like this, which are frequently just ways to load malware, I always make sure I download from a reliable site, such as Sourceforge, FileHippo or MajorGeeks.

Nothing is entirely reliable, but I've never had any problems with these.