Turned the furnace on today for the winter and it makes the usual noises and top motor turns but bottom doesn't and burners don't ignite.

Filter is clean, 4 flashing red lights on LED. (High temp switch)

Is it that simple that I need a new high temp switch given the symptoms described?

Help Appreciated.

The hi-temp limit tripped when the blower quit working. You need to diagnose the problem with the blower. You could need a new motor or fan relay. If you change the blower make sure to change capacitor with it. Buy an oiler and oil motor before you install it, and clean out oil holes before you put oil in. Many times the motors come with too little oil in them and need a little oil. Make sure to clean blower yearly, pull motor and oil it and you won't have it going out on you.