vtsguardabosc wrote:

Hello everybody. I'm new at searching for little green men (and
women).
Half an hour ago my computer (Pentium III Celeron 700 MHz)received the
data for the first data unit. It started analyzing the data and, after
six minutes, when the 0.400% overall (aproximately) was completed, I
decided to press F1 for help. In this very moment, the screen said
that the analisys was complete, the computer sent the data back to
SETI and it received the second data unit.

If the analysis detects something that renders further analysis useless it will stop working on the first unit and begin another one.  You will get credit for the first unit too.  If you are using BOINC you can see many details about the units by clicking on the unit from your computer page.

Example:
http://setiweb.ssl.berkeley.edu/workunit.php?wuid=9367734