I CANNOT START SESION IN MY COMPUTER

I didn't refrsh my computer, my trisquel is pretty old.

As far as I understand https://packages.ubuntu.com/busybox-udeb your version of busybox-udeb is older than that in Ubuntu 18.04 (on which Trisquel 9 is based). Trisquel 8 is not supported anymore. For seven months now, it has not received any update, in particular security update. You want Trisquel 9.0.1. Its ISO is on https://trisquel.info/download (unless your machine is really old, you certainly want the 64-bit version, unlike the version you currently have), https://trisquel.info/en/wiki/how-create-liveusb explains ways to create a live USB from it and https://trisquel.info/en/wiki/starting-installable-live-system how to boot it.

Nevertheless, before installing Trisquel 9 (on top of the older version you have or, maybe, taking the whole disk) you want to backup the user data! You can do that from Trisquel 9's live system: the partitions on your internal drive(s) should be accessible from the file manager and you can copy-paste all the user data to an external drive (or to a remote machine, through the network). Only after the user data are safe somewhere outside the computer (and you checked they are readable), you can proceed with the installation of Trisquel 9, double-clicking on the related icon on the desktop in the live system.

Again: you really want to upgrade to Trisquel 9, because Trisquel 8 does not receive security updates anymore. See https://trisquel.info/forum/upgrade-80-90-questions for ways to upgrade from your running system.