Thanks for your advice, I felt safe, because I had Bitdefender anti virus programme installed, but that one completely disappeared. Looks like the attacker could delete it.

My bitcoins went to this address:  1GgJkUADnzZ6kNF13toGpv7o8bCj3WYQov

One attack came from this IP: 51.21.9.22 Netherland, NL
Second one from here: 198.38.94.199   ALAMO, CALIFORNIA, UNITED STATES   2015-04-09 06:59:08 EST

Can somebody help me to trace this guy ?