I think I did something stupid when I was experimenting with a new wAP. I tried to downgrade from 6.33.5 to 5.26 just for fun and now I cannot access RouterOS using Winbox. Is it possible to in some way restore the device or shall I throw it away?
wAP doesn’t support ROS 5.x AFAIK.
You should try a netinstall: http://wiki.mikrotik.com/wiki/Manual:Netinstall
I have already tested a netinstall, but without luck. On the other hand, I’m not 100% certain that I do this right.
netinstall can be tricky sometimes, how long are you maintaining the reset button pressed after power-on?
wireshark would be useful to detect if the wAP is entering netinstall mode (watch out for DHCP/bootp packets)
According to the manual (http://i.mt.lv/routerboard/files/wAP-series.pdf) it’s either 5 or 15 seconds, which I have tried.
Success! I followed your advice and installed Wireshark and started to capture/listen for bootp packages and then boom! Lots of packages where captured in my net!
I was then was able to install the firmware to the device. Thanks, pukkita! 
Glad it helped! Usually 30 seconds is what it takes.