We have a Cisco Catalyst 3550 series, and we don't have the password to gain access to the switch through a web browser. My question is if I reset the password using Hyper-terminal, does changing the password affect any vlan or fiber optic settings that I should know about. Or does resetting the password changes our switch to factory settings?
The password recovery procedure for your switch is described in this document:
If you follow the instructions in the document exactly, you will retain the original configuration - you just rename the configuration file so that it is not loaded when the switch boots up. However, you will still be able to display it after the switch boots up using the more flash:config.old . Eventually, you can even load it into running-config using copy flash:config.old running-config command. At that point, the old passwords will be brought back but because you already are in the privileged EXEC mode, you can change them and save the updated configuration.
VLANs should not be affected as long as you do not delete the vlan.dat file located in FLASH. Fiber optic ports should not be affected as long as you are using original Cisco GBICs. If you're using 3rd party GBICs, it may be necessary to enter the service unsupported-transceiver hidden command in the global configuration mode before they get recognized.