Powercycling as in 'unplug mains supply', either at wall or pulling out power connector from the back
That should clear any connection issue.
My wrt54g doesn't (touch wood) have any issues on 2Mb NTL.
Next time, try browsing to the router admin page - this should show whether the router is hung or just the connection. Then try unpluging the Cable Modem followed by the router.
HTH