Mikrotik RouterBoard Freezes

Hi,
Can someone shed some light on the cause of the below behaviour that i have been experiencing on the mikrotik network that i run.

The Routerboard freezes and can only come up after a hard reboot(When I remove the Power and then inject it back).
The link comes back up pefectly though it recurrs after some days.This is affecting several routerboards n costing me downtime at unpredictable hours.
Is it hardware or a software issue??

Help me get a fix to this…

Cheers.
skypeid::OnzereJnr

Upgrade the firmware to latest, upgrade the software to v3.30 or above. Maybe things change. If no different, then sounds like either the wireless cards are crashing the board or it is a routerboard problem. Also check PSU voltage and power capability is correct for the board and number of cards. It is possible that voltage is dropping when cards transmit and causing crash.