Need better picture on secondary monitor

It's not the monitor's fault and it's not the cable's fault.  The problem is in VGA itself.  Regrettably there is no solution for this other than to stop using the VGA port, buy a USB to HDMI video adapter, and use that for the second monitor instead.

VGA goes back to the days when analog TV was the standard.  As such it has problems.  At 640x480 it was OK; at 800x600 it was tolerable; at 1024x768 it was already looking less-than-good.  It is just not possible to slam around an analog signal fast enough to support modern monitor resolutions.  The result is smearing and inter-color aliasing, objectionable artifacts where color changes significantly -- and the higher the resolution gets, the worse the problem looks.

the hdmi port is taken now.  there are some usb-c - looking ports open though

You haven't provided a picture to see the difference, but personally, I find VGA is fine 99% of the time.  It COULD be the cable's problem.  It could be a problem with the monitor.  The issue I most often see with VGA is color can differ especially when using a digital connection at the same time (with otherwise identical monitors).  It could also be that you have the monitor's resolution set sub-optimally.  For example, you could be using 1024x768 on a Full HD screen.  Screens look best when they are displaying their native resolution.

That said, keep in mind, the VGA connection is roughly 30+ years old.  It's not new technology.  It's also analog and more subject to interference from other sources.  That said, I would probably suggest getting a multi-(digital)-monitor capable docking station and use that.  Or a USB graphics adapter.  Plenty of options exist for USB 3 and USB C, though the standard your laptop has will potentially affect the maximum number of monitors and the resolution those monitors can display.

I have the resolution set to the highest and I've tried everything else and it's still just looks terrible.

I really do need to get the dock for this zbook. I was using a dock when I was working in the office and now my job is switched and I'm working at home and I forgot the dock at work so I need them to send it to me. I think there's a DVI or other HDMI ports on the dock

But remember as Dr Klahn states the higher the resolution is on the vga the worse it is going to look as far as the vga connection is concerned. 

VGA is an analog signal and it needs to be lined up on the monitor.  There is either a button on the monitor or a function in the monitor's menu system to align the signal with the pixels on the monitor.  When you select the function, you'll see the image move very slightly sideways.  When the signal and the physical pixels line up, the monitor will lock on to it.

comp, can you give more detail on the steps to take?

If you will provide the make and model of your monitor I may be able to do so.  Some monitors have a dedicated button (often labeled "Auto") while others have it embedded in the menus.

i see "Auto"

VGA was good for CRT based analog monitors. VGA resolution is 640x480. SVGA is 800x600 or XGA is 1024x768.. VGA was introduced in 1987 on the PS/2 Line of IBM PC's.  https://en.wikipedia.org/wiki/Video_Graphics_Array#Standard_text_modes_2

When dealing with flat panel displays using plasma/LCD/LED technology one wants to match the display resolution to the native resolution of the panel itself for the best results.

You didn't say which zbook you have but they all seem to have display port outputs or thunderbolt (which can be used for display. You can buy display port 2 hdmi adapter cables.

Which generation ZBook? Later generations have Thunderbolt available. Hmm, there again the later ones don't have VGA.

G15

okay just lower the resolution on the AOC monitor in the new monitor shut off and is in kind of a sleep mode and won't wake up. I did a restart and I can't get the new monitor to come back on

if I unhook the video cable for the main monitor then the new one comes on. but all of the video settings are grayed out now

now I've got myself into a mess

It's only up to G6, the 15 probably means 15 inch, If you enter the serial no at https://support.hp.com/us-en it will tell you the generation.

It's a G4

use the display ports on the right side (Thunderbolt 3)
(1) HDMI 1.4
(2) Thunderbolt 3 (supporting DisplayPort 1.2, USB 3.1 Gen2, PCIe Gen 3 devices)
(1) Stereo microphone in/headphone-out combo jack
(1) Power connector
(2) USB 3.0

David Johnson, CD is the Thunderbolt the port that looks like the new USB C or 3 or whatever?  (I still dont have the dock yet)

see multi-display support in https://www8.hp.com/H20195/V2/GETDOCUMENT.ASPX?DOCNAME=C05381086

Thunderbolt to HDMI adapters cost $10.

Does anyone know what this paragraph means?
Without ZBook Dock with Thunderbolt™ 3 (using DP 1.2 MST)
Multi-stream Transport is a DP 1.2 feature that allows daisy chaining of DP 1.2 monitors that are Thunderbolt™ 3 enabled
(requires built in support of DP 1.2 MST in monitor), or the use of DP 1.2 hubs (Thunderbolt™ 3 enabled) with MST to achieve
6 active displays without a docking station on configurations with hybrid graphics enabled.

Amazon has a good deal on the docking station https://www.amazon.ca/dp/B07JVJ1V53/ref=dp_cr_wdg_tit_rfb
Startech makes an adapter https://www.startech.com/ca/AV/display-and-video-adapters/thunderbolt-3-video-adapters/thunderbolt-3-to-dual-displayport~TB32DP2T

David Johnson, CD Thank you .... I should've ALSO mentioned that I moved my work desk from the office to home.  My mgr forgot to put the dock in the bag.  He will be sending to me soon, hopefully.
:)

David Johnson, CD is the Thunderbolt the port that looks like the new USB C or 3 or whatever?

Have you set Windows to display on the correct resolution for the monitor and had the monitor perform the alignment?  VGA won't be as sharp as the digital methods, but may be good enough when set correctly.

Yes it looks like the USB-C connector

compProb, yes... if I fiddle with the everything goes to heck

David Johnson, CD ....can those usb 3 ports be used for video at all?

They are not USB3, they are Thunderbolt which is a superset of USB,

From the spec:
(2) Thunderbolt 3 (supporting DisplayPort 1.2, USB 3.1 Gen2, PCIe Gen 3 devices)

How cheap an adapter do you want? https://www.amazon.co.uk/uni-Type-C-Compatible-MacBook-Surface/dp/B075V5JK36?ref_=fsclp_pl_dp_5 but there are some for less than $5.

andyalder Oooh ok, I see.  thanks.  So this will handle the video just like my other monitor that's on hdmi?

Should work fine with any Thunderbolt to HDMI. I haven't tested it as can't afford a Zbook ;)

There is a USB3 charging port but the Thunderbolt ports are oval and have a lightening bolt symbol next to them. It does not matter which way up you plug it in, Thunderbolt plug works either way.

the cable from the monitor is DVI

A connector like this? You have to be careful as many say Thunderbolt to DVI but when you look at the picture they're actually mini displayport to DVI,
https://www.cablesdirect.com/store/p/4777.aspx

andyalder, I BELIEVE so.  The laptop port looks like usb C and has a little lightning bolt icon by it.

I had to buy a $20 adapter that goes from DVI to USB c

Thank you all, for the great assistance.