Can't connect to U28D590D screen

Use an HDMI cable

im using a displayport and no thats not working ;)

Does the system have a make and model? The thing Ubuntu is installed on? Do you just get zero image on the screen?
What video chip are you using?

no, I can't connect to my screen at all.

I have a lenovo w520 computer with 2 video cards:

NVIDIA QUADRO 2000M 2GB VRAM with 192 CUDA CORES

Intel(R) HD Graphics Family

00:02.0 VGA compatible controller [0300]: Intel Corporation 2nd Generation Core Processor Family Integrated Graphics Controller [8086:0126] (rev 09)
 Subsystem: Lenovo Device [17aa:21d1]
--
01:00.0 VGA compatible controller [0300]: NVIDIA Corporation GF106GLM [Quadro 2000M] [10de:0dda] (rev a1)
 Subsystem: Lenovo Device [17aa:21d1]

Sounds like a laptop. Is that right?

Can you please answer all my previous questions rather than just one....

Well, those questions I haven't answered I didnt understand, sorry. Yes, its a laptop.

What make and model? As I asked in #3

as I wrote before:

lenovo w520 4284-49G

lenovo w520 4284-49G or else I haven't understand what you mean by make and model, sorry.

If you have a switching GPU then you will need to look into nvidia prime

If you hit the shortcut on the keyboard to switch between laptop and the screen, does it send the display?

Well, its currently only using NVIDIA Quadro 2000M. What shorcut are we talking about?

sadly, still no connection between my laptop and external sceen :/

This question was expired because it remained in the 'Needs information' state without activity for the last 15 days.

well, thats because i didnt got a reply.

Please provide the output of the commands

uname -a
lsb_release -crid
sudo dmidecode -t 1
sudo lshw -C display
xrandr

Sorry, for not answering sooner. Following show outputs of these commands, BUT I removed serialnumber and UUID.

uname -a

Linux mark 3.19.0-25-generic #26-Ubuntu SMP Fri Jul 24 21:17:31 UTC 2015 x86_64 x86_64 x86_64 GNU/Linux

lsb_release -crid

Distributor ID: Ubuntu
Description: Ubuntu 15.04
Release: 15.04
Codename: vivid

sudo dmidecode -t 1

Handle 0x0010, DMI type 1, 27 bytes
System Information
 Manufacturer: LENOVO
 Product Name: 428449G
 Version: ThinkPad W520
 Serial Number: (removed)
 UUID: (removed)
 Wake-up Type: Power Switch
 SKU Number: Not Specified
 Family: ThinkPad W520

sudo lshw -C display

*-display UNCLAIMED
       description: VGA compatible controller
       product: GF106GLM [Quadro 2000M]
       vendor: NVIDIA Corporation
       physical id: 0
       bus info: pci@0000:01:00.0
       version: a1
       width: 64 bits
       clock: 33MHz
       capabilities: pm msi pciexpress vga_controller cap_list
       configuration: latency=0
       resources: memory:f0000000-f1ffffff memory:c0000000-cfffffff memory:d0000000-d3ffffff ioport:5000(size=128) memory:f2000000-f207ffff
  *-display
       description: VGA compatible controller
       product: 2nd Generation Core Processor Family Integrated Graphics Controller
       vendor: Intel Corporation
       physical id: 2
       bus info: pci@0000:00:02.0
       version: 09
       width: 64 bits
       clock: 33MHz
       capabilities: msi pm vga_controller bus_master cap_list rom
       configuration: driver=i915 latency=0
       resources: irq:38 memory:f2400000-f27fffff memory:e0000000-efffffff ioport:6000(size=64)

xrandr

Screen 0: minimum 8 x 8, current 1920 x 1080, maximum 32767 x 32767
LVDS1 connected primary 1920x1080+0+0 (normal left inverted right x axis y axis) 344mm x 193mm
   1920x1080 60.0*+ 59.9 50.0
   1680x1050 60.0 59.9
   1600x1024 60.2
   1400x1050 60.0
   1280x1024 60.0
   1440x900 59.9
   1280x960 60.0
   1360x768 59.8 60.0
   1152x864 60.0
   1024x768 60.0
   800x600 60.3 56.2
   640x480 59.9
VGA1 disconnected (normal left inverted right x axis y axis)
VIRTUAL1 disconnected (normal left inverted right x axis y axis)

For system like yours with two graphic cards you need additional software like bumblebee https://wiki.ubuntu.com/Bumblebee or nvidia-prime https://wiki.ubuntu.com/X/Config/HybridGraphics