When I try to launch any version of minecraft with the new launcher it says it cant download.

Please do not mark unreleased versions as affected.
You don't have access to them yet.

Please copy and paste the entire error message here.

its always different error messages but here is one of the messages:

Unable to save download. es_mx.lang
Name: es_mx.lang
URL: http://resources.download.minecraft.net/7b/7ba2f702d30a42b6ecd8762a8fe075e54cc14520
Error details: Attempting to move successful download to C:/Users\Name\AppData\Roaming\.minecraft\assets\objects\7b/7ba2f702d30a42b6ecd8762a8fe075e54cc14520
The process cannot access the file because it is being used by another process
Filename on disk: ff72-6389-d734-3038
Path: C:\Users\Name\AppData\Local\Temp\ff72-6389-d734-3038
Exists: file

how was this resolved I have the same problem

It's a duplicate of MCL-5367. There is much more information on that ticket.

but how do you fix it

This is a bug tracker, not a help desk. Contact Mojang's help service if you need help.