My phone wont let me transfer files from my computer..

[Android Central Question]

My phone won't let me connect to usb so I can transfer my files from my computer... I have tried everything.. I have tried different cables, changing settings... Everything. But still nothing... My phone used to do it a few days ago but now nothing... I have changed all the settings and it will charge but it will not have an option for all the different options so you can select the MTP. What can I do...