I need to reboot the pc and I don't would like to lose the portion downloaded until now.

Is it possible retry the download again if I close Xolox and reboot the pc?

THANKS!

thats what xolox is good at.

back up the text files in the xolox application directory.
they store info like hosts, partial download status etc.
and sometimes they get corrupted.
if these get currupted then you have problems.
otherwise should not be a problem