Thank you very much for quick reply and for the link. I run obsolete system on obsolete computer but it still have some uses - for example I am not afraid it might get damaged somehow or if someone were so stupid to steal it it won't be such loss ;-) But it's not worth buing newer OS for it and I feel too old to learn Linux.
According to Wikipedia BitTorrent Sync works for Windows XP SP 3 and higher but it looks like it is no longer true. I downloaded the 32 bit Windows version but it doesn't install. Is it possible to get some older version of Sync that runs on Windows XP? I didn't manage to find it on the getsync.com. Will it be compatible with the new version I have on my new computer/mobile phone? Thanks for help.