Things that are acting oddly that may be Vista related

Ok, I know this is kind of a newbie post, but I just cannot look at a list of things wrong with Vista and understand which of those apply to me. Partly it's me not understanding the jargon, and partly it's because the list is just too big. So maybe a simple newbie will help some others out there.

#1 When I'm watching a movie or a video, and I slide the thingy too far either way WMP (windows media player) crashes. Sometimes the video will freeze, sometimes it 'glitches' (idk the term) where it plays a second of the video over and over again, and sometimes the screen will just go black (sometimes it'll go black and the audio will still be playing, other times no). So when I want to skip to a different part I have to move the slider like an inch each time, I can't go straight from the beginning to the end.

#2 Media Center crashes pretty much everytime I try to play a video or movie

#3 Sometimes just as I'm turning on/starting up the computer it'll finish loading and booting up then the screen will go black. When this happens, it either 1) goes back to the 'enter your password' (or in my case slide your finger screen)' or 2) screen will go black and it'll restart itself. 3) it goes black, pressing the keyboard won't start it up, the power light will blink, sometimes I gotta turn it off myself, sometimes it'll turn off itself.

3) After WMP crashes, I can't open it again. I have to restart the computer before I can do this. This happens when IE crashes too.

My laptop:

Sager NP2090
T7300 2.00GHz
2gb ram
Vista Home Premium 32 bit