Which port are you using to connect to it?
Have you tried a port other than ether1? (as ether1 is usually WAN and so, firewalled on default config)?
Do you see it on winbox neighbors tab? Can you connect to it from winbox if you double click on the MAC field while in neighbors tab? If you can't, what's the error?
To reset to defaults:
1.- Unplug power
2.- Press reset button, kept it pressed
3.- Plug Power,
4.- Keep pressing until led starts blinking (never resetted a 4011, don't know if PWR LED flashes, but this is the usual way)
If this fails, you'll need to resort to a netinstall
, which will format the NAND and reinstall ROS on the device with default settings.