Ender 3 V 3 .Programed USB not showing any info on screen

This 3 V 3 printer has been working OK .But now I can not load any files onto it .
I use the USB stick method to transfer files ,but now the printer does not show (see) any of the files that have been loaded. (have tried several USB 's) I have tried to do a factory reset but cant find out how to .I do not see it on the menu. Any idears
??

Hello britinoz,

I don’t have that model, but the v3SE is funny with the size of USB stick/SD card and will only work with 8GB or smaller.

Cheers.