You're going to have to give us more info.
What exactly do you mean by "will not open attachments"? PowerPoint opens PPT files, PPS files, some DOC files, TXT files, etc., but "attachments" can mean a lot of different things. So can "will not open." Add to that your mention of "when I'm in my online PPT class," and you've inserted an entirely new dimension to the problem.
So, step-by-step, please describe what it is you're trying to do and what is happening when it fails.
Same with "will not insert clips." That covers a lot of area. How are you trying to insert the clip? What happens when you do that?
What version of PPT are you using?