i also tried to create a complete new windows user and testet another steam account from a friend at my pc it didnt run. i can run dayZ on his pc without problems with my steam account.

my PC spezifications are:
Betriebssystem
Windows 10 Pro 64-bit
CPU
Intel Core i5 4460 @ 3.20GHz
Haswell 22nm Technologie
RAM
8,00GB Dual Kanal DDR3 @ 799MHz (9-9-9-24)
Motherboard
ASUSTeK COMPUTER INC. H97-PRO (SOCKET 1150)
Grafik
LG ULTRAWIDE (2560x1080@60Hz)
2047 MBNVIDIA GeForce GTX 770 (MSI)
Speicher
223GB Crucial_CT240M500SSD1 (SSD)
931GB Western Digital WDC WD10EADS-22M2B0 (SATA)
298GB Western Digital WDC WD3200AAKS-75L9A0 (SATA)
Optische Laufwerke
DTSOFT Virtual CdRom Device
HL-DT-ST DVDRAM GH41N
Audio
Sound Blaster Z

i have done everything but didnt change anything :(

No i get no messages. the only message is in dayZ and it says: Confirmation of Changes - Session Lost