The first two issues sound like a video driver problem.
What is the make/model of your video card/chip?
What is the installed video driver number and date?
For the last issue, it could be many things, including the video driver. I'd look over this ARTICLE, and if there is nothing in the first part, then move on to tuning up the OS an computer in the second part. That would probably be a good time to post the full specs. of your computer, and also both your Project and Source footage. Finally, part three covers many troubleshooting tips, and furnishes many links.
I got it all figured out. Everything is fixed.
katey, I have the same problem (transitions not loading)... how did you fixed that?