THE PROBLEM

If you have one of the nvidia cards listed here:

http://us.download.nvidia.com/XFree86/Linux-x86/173.14.25/README/appendix-a.html

So you have an old one. LMDE is based on Wheezy, and it comes with the Nouveau and Vesa free drivers for the nvidia cards (see more in : http://wiki.debian.org/NvidiaGraphicsDrivers). This is the reason of the message "Unable to enumerate usb device on port X", the drivers doesn't recognize the card.

Nouveau and Vesa free drivers have compatibility problems with the legacy nvidia drivers (the drivers for old cards).

and if you install'em together your graphics will disappear once you restart the system, and instead you'll find a non-ending list of 'Unable to enumerate usb device on port X' messages. 

THE SOLUTION

Note: I'm not a Linux master, finding this solution took me several days of installing and uninstalling LMDE, so the next tutorial is from a guy with little Debian knowledge to other inexperienced people, so if you got simpler or better ideas, please suggest and don't feel attacked by my post. I just try to give back Debian/GNU Linux what it has given to my life by means of solutions to the problems that the users can confront.

In any case i suggest re-install LMDE and when done, open a terminal an run the steps below.

Just copy and paste the coloured paragraphs. Note that there are # and $ symbols, wich idicates commands as super and common-user, respectively.

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Case 1

If you didn't experiment 'unable to enumerate...' messages in the run of the installation and have already installed the legacy drivers (either step by step or via Nvidia-settings) you can remove the drivers in the recovery mode:

# aptitude purge nvidia-kernel-legacy-173xx-dkms nvidia-glx-legacy-173xx build-essential nvidia-settings nvidia-xconfig

 

or if you installed Nvidia settings:

# aptitude purge nvidia-settings

# reboot

This must lead the things as they were in one instance, now you can run the steps below in one terminal. But if the screen doesn't comes back, reinstall your LMDE.

Case 2

But if you just have lots of 'Unable to enumerate ...' messages, the best you can do is re-install LMDE in order to avoid problems while writtng the commands.

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Open a console and enter as root

I suggest first remove Nouveau (i used 'purge' instead of remove, if there are no files close-related to nouveau it will work exactky as 'remove', but if for a reason there are files related to the driver, you'll still have problems of compatibility), then remove Vesa and finally install the legacy drivers:

# aptitude purge xserver-xorg-video-nouveau

# reboot

Your screen will looks better now but will be too small, don't worry it wont be long. Now remove Vesa

# aptitude purge xserver-xorg-video-vesa

# exit

This will led you as a normal user. We must add a non free repository to the sources list:

$ gksudo gedit /etc/apt/sources.list

Enter your super-user password. One gedit file wil open, add these lines at the end of the file:

deb http://ftp.us.debian.org/debian testing main contrib non-free

save and close.

Then, back to the terminal and log as root. Make an update:

# aptitude update

and then run

# aptitude install nvidia-kernel-legacy-173xx-dkms nvidia-glx-legacy-173xx build-essential nvidia-settings nvidia-xconfig

 

When done, execute

# nvidia-xconfig

# reboot

After reboot, the legacy driver is working and your screen looks great. Good luck!