How to reset to factory conditions without a remote a panasonic SAHT74

I would try searching on the companies official website to see if there is a remote and an instruction manual for your Panasonic Blu Ray player.

Standard Panasonic factory reset is hold the local volume down button (Function, then channel down), whilst pressing the info (i) button on the remote control. There should also be a shipping condition reset on the user menus

You need the remote you can most likely get a factory remote here: 1 800 Remotes

Just try a reset to this TV.
To do a hard reset, just unplug the TV from AC mains wall socket, and re-plug it back after 15 minutes or so.This procedure will make it a hard reset.If you want to make it a system reset [Factory Reset]; you have to enter its service mode option, and select the factory reset option.If you wish to get some details; check the site linked here.Pull up older posts.Surf the site with patience.http://electronicshelponline.blogspot.com/
Service mode entry, adjust and exit procedure to many popular brand TVs are given.Never forget to exit the service mode, after all adjustments have been done.

Restore to factory settings
To restore the phone back to factory conditions, select Menu > Settings > Rest. factory sett. and from the following options:
Restore settings only -0 to reset all preference settings without deleting any personal data
Restore all - to reset all preference settings and delete all personal data, such as contacts, messages, media files and activation keys

• Reset the unit to factory default settings as follows:

1. Press [POWER] on the unit to turn off the unit.
2. Press and hold [FAST FORWARD] and press [POWER] and [OPEN/CLOSE] on the unit at the same time for more than 5 seconds until "PLEASE WAIT" is displayed on the unit.
3. The power is turned on and then turned off automatically.

http://service.us.panasonic.com/OPERMANPDF/SCBT200.PDF

Without its original remote control, you can't do anything including entering its service mode option. To get some details, http://electronicshelponline.blogspot.com/Pull up older posts.

Check and replace the remote sensor inside it. It might be faulty.
These are images of some types.

You can try to reset the unit to factory defaults (you may require the user manual for this) or you can try to reprogram the remote to match the 'MODE3' or 'DVD3' display on the unit itself.

While the unit is on, point the remote at it, press and hold both the [3] button and [ENTER/OK] button - TOGETHER for 5 to 10 seconds, then release. Should work. Failing that, refer to the user manual for resetting the unit to factory defaults (if possible without the remote) - this manual should be available from the Panasonic website as a pdf. - free.

Try the above suggested step with the remote first. Hope this helps a tiny bit.

Is there a menu button on the front of the tv? If so press the menu button and look for options in menu mode.