I am completely new to Boinc and Bam and I am not yet exactly sure how all this works.But I have signed up for about 5 different projects one of which is the BBC Climate Change Experiment and when I click on the tasks tab in the BOINC Manager it says that it will take 3617:24:19 hours minutes and seconds to complete the task for it.How will my computer complete this task unless it runs only that project for about a year and what about the other projects.I need instructions.

1 year is 8760 hours, so you can crunch more then 2 WUs if you run CPDN (or BBC) exclusive on a 24/7 machine.

But afaik the deadline is less strict with it, but you will have some time with only this one crunching once the "overcommitted" status is detected in BOINC.

BBC is one of the most demanding projects regarding puter power, that's for sure.

Is there a mean to safely transfer a started task from one computer to another faster one without losing this pending task ? I have downloaded a couple of time consuming tasks on a slow computer, and I would like to end those computation before I die by old age

@ dprikhodiko - general approach is quite easy:
If you have not installed BOINC as service (i.e. run via shortcut), just move whole BOINC folder to another machine.
In case of service installation: stop BOINC service, backup whole BOINC folder; install fresh BOINC on a new computer, overwrite folder content with backup.

Many thanks. Indeed it sounds very easy.
I was thinking that each started task (or WU) had been assigned to a single computer (the host ID number, I mean the computing host which refers to the pending task) and could not be changed...
I wonder why ?

But if the Boinc directory with all WU files can be moved from one computer to another without losing all preempted tasks, it is really fine !! Thanks for your friendly help.

What Happens if I cannot complete the task before the deadline?

You will get tarred and feathered

It depends on the project, in the mentioned climate experiment afaik nothing, the credits achieved through trickles will stay in any case, and the completion of the task is as well possible.

In other projects the WU will be sent again to another cruncher, and after validation they will be deleted, later arriving WUs will not be taken. If validation is/was already possible with the results already in they will not take late arrivals as well.