Hikvision nvr DS-7604NI-SE / P crashes hangin up

Hi,

I have a hikvision nvr ds-7604ni-se/p installed with 3 hikvision ip camera's 3 mp.

the problem are after 2 days the nvr are crashing/hanging up. after this i must be restart the system and then its working again for couple of days and crashes/hanging up again,

and i need to restart again.

i upload the last firmware. this is ok.

can someone help me???