Reset A Cisco Catalyst switch to defaults.

Dead easy this one.

to clear the config

#write erase

then

#del flash:vlan.dat

I actualy back up both the config and vlans beforehand

copy run flash:config.old
copy flash:vlan.dat flash:vlan.old

just in case....

http://www.cisco.com/en/US/products/hw/switches/ps607/products_tech_note09186a00800c4546.shtml