Hi there!
I came across a curious problem these days. I bought a USB mouse and keyboard to replace my old serial port ones. The very first days I had them installed the system worked well. Then recently the problem appeared. After selecting the system to boot, in the GRUB list, the computer restarted as many times you wanted to boot. Then I tried to disable the serial ports on the BIOS and do some other minor changes, but it didn't help. Then I tried using the old keyboard and mouse again and the system booted normally.
Is there anything I can do?
Thanks in advance.
Best regards
darthpinguim
P.S.: Happy New Year!!!

while your serial keyboard is booting up...go into bios and enable
usb legacy

save and reboot ....even if that does not solve your problem ....it will let you get into your bios using an usb k/b.

2) are you using grub legacy or grub2?

maybe you need to mod your grub2 to include

insmod usb
insmod usb_keyboard

leaping ahead....use root powers to edit your /boot/grub/grub.cfg but do not run update-grub
reboot to test

if it solves the issue report back and we need to mod an /etc/grub.d file

Hi aus9, thanks for the reply and happy new year!
USB legacy was already enabled in the BIOS.
Now concerning the modification on the grub file, where should I include those lines in the grub.cfg file?

sorry been away

in the gap

#
# DO NOT EDIT THIS FILE
#
# It is automatically generated by /usr/sbin/grub-mkconfig using templates
# from /etc/grub.d and settings from /etc/default/grub
#

### BEGIN /etc/grub.d/00_header ###

remember do not run update-grub at this stage please ....you are testing to see if usb works at grub screen

report your results pls

2) I assume you have a live cd and so can easily re-edit if my advice is bad?