Disable or preferably uninstall and anti virus/spayware apps. Kill all background apps (msconfig). Defrag your hardrive and make sure it has 30% free at least.
Your computer will run AE ok…just not with Vegas open.
I dont know of 7200 internal drives for laptop. Many folks use external USB drives with laptops.
Without knowing the properties of your video and your hardware specs it is difficult to help.
Having Sequence settings match the properties of your video is a good starting point…also 59.94 fps is unlikely for 1080i which has no fields.
Deleting audio linked to video is pretty hard to do accidentally. You could have accidentally dragged the audio to track 3 or below and cant see those tracks without scrolling down using the scroll bar at the right end of the timeline.
I agree with Daren, Auto levels is bad for video, but for some strange reason it works well with video of film which flickers badly on its own and Levels makes it worse…try it…mikey likes it!
Try speed/duration…right click on the clip and choose that. Do a little math…1 second off = X%. Enter that % in Speed…positive or negative. Might take a few tries and also might not work if frames were dropped on DV capture.