I am new to linux and am trying to get help with a problem that I have been working on for awhile. I am supossed to use awk to find the average gpa. the file is set up so the the letter grade is in field 4 and the courses credits are in field 3. The command below is the last one that I came up with but it prints out the GPA is nan. I am just not sure what i am doing wrong.

My Firefox (3.0.3) completely freezed, so I couldn't kill the process (or there was no proces to be more presice).

Then I deleted .parentlock and now I can start Firefox up and surf etc., but I CANNOT add bookmarks, use the google search field next to the address bar and some other stuff.
And every tab I have open (except the first one) have the loading (rotating thing) on it all the time.

I've tried to remove it completely and did a fresh install, but no luck...????