2-i meant the completed portion of those tasks. if I wanted to EV for july, I would take the "completed portion" of those tasks that took place in July and add them correct? or, is it a cumulative amount, so the amount shown say on July 25 would include the amount in July 24 plus that day?

I'm afraid I don't understand your question. The earned value (BCWP) is only calculated on the work that is actually performed. You can see earned value data in a timescaled view to see what the earned value was as of a certain date and status date.

3-again, i meant when it is complete. so when the task is complete, in that instant BCWP would be equal to the fixed cost i had assigned in the beginning when saving baseline correct?

Only if the work was completed as originally scheduled. If you finished the task before the original finish, then the BCWP could be greater than the BCWS and you would show a positive schedule variance when the status date = task finish date.

If you took longer to complete the work then the schedule variance would be negative.

4-did not understand your answer to this one. BCWS or in other words PV, is totally dependent on baseline, isnt that so? so what is the relevancy of status date here?

No. All earned value data is as of the status date. If you have a task scheduled for the future and the status date is today, the BCWS will show zero - there is no work for that task scheduled for today. BCWP is also as of status date and tracking.

To illustrate, create a simple, one-task project. Project start date was last Monday August 13, 2012. Task duration is 5 days. Assign $50 fixed cost. Save the baseline.
Set your status date to August 10, 2012 and you will see zero BCWS. The tasks is not scheduled to start until August 13.

Set your status date to August 13, 2012. You will see BCWS = $10. You were scheduled to spend $10 per day for 5 days so your current BCWS is $10.00. Mark the task 15% complete. The BCWP = $7.50. By the end of the first day, you should be 20% complete but you are only 15%. You've only earned $7.50 instead of the $10 you should have earned by the end of the first day.

Set your status date to August 14, 2012. You will see BCWS = $20.00 and until you update the % complete the BCWP = $7.50. Update the % complete to 50% - Project is going to assume you have actually worked through mid-day on Wednesday. Set the Actual Duration to 2 days and remaining duration to 2 days. The finish date of the task moves in and now you BCWS = $20 but the BCWP = $25.00. You are currently ahead of schedule - you've accomplished 50% of the work in less than the original 2.5 days.

If all you do is mark % complete -- Project will assume everything went according to schedule and BCWP and BCWS and ACWP will be equal.