Without a remote control, you can't do a reset.
If you wish to buy its original remote control, contact the authorized service centre, or authorized dealer to your device brand. They can either give you a genuine remote control to your device, or can direct you, from where can you purchase a suitable one.
To select a proper universal remote control, you should know about the number of digits to its set-up codes. There are 3 digit, 4 digit, 5 digit, 2 digit and even single digit codes, to some brand devices. After confirming this, check the sites linked here. Both the sites have set-up code list and set-up procedure to many popular brand remote controls. Check which brand remote control has set-up code/s to your device brand, and buy that one according to availability. Brand name of the remote control isn't a matter, but it should have set-up codes in its code list, to the device brand you have.
Please note: Every new universal remote control will have set-up code list, and set-up procedure along with its pack. Never accept a remote control, that hasn't both of this. For more details about the set-up codes, visit the sites.
Universal remote controls are available at most of the electronic spare part selling shops. Visit some on-line sites too, which deals with electronic spare parts.
There are two methods to reset TVs. The first is simple to do; a Hard Reset. The other is somewhat skilled; is a Factory Reset (System Reset). To make it a hard reset, just unplug the TV from AC mains wall socket, and re-plug it back after 15 minutes or so. If you do this by overnight is better. 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.
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.