Some tips about Ubuntu server | or it may works on other Linux distributions too

Mount USB-HDD/USB-flash disk to Ubuntu Server:
1, plug the hardware
2, run below command, see which maybe the device name
Tail-F/var/log/messages
3. mount it
Sudo Mount-T <file system type | vfat> <device name |/dev/sdb2> <path to mount |/mnt>

Install linux header files (maybe for VMware Server ):
1, run
Uname-R
2, run
Sudo apt-Get install linux-headers-<output from the last command>

removed your only account out of sodoers:
1, reboot machine.
2, Press ESC when grub loading
3, select "recovery mode (single root)" mode
4, run
usermod-G admin
5, exit