i have an error pop up when i try to start, it says

The file Client.dll could not be setup properly.

no available render modes detected.

the application is now shutting down.

anyone have any clue on what to do?

thank you

No! Wrong! Bad!

The problem IS a video issue. There are 3 main causes of this issue:

1. Your video card doesn't properly support MxO.
2. Your DirectX installation is corrupted or damaged.
3. Your video drivers are faulty or damaged.

How to diagnose:

1. If you have successfully run MxO in the past on your video card then obviously your card is up to it and this is not the problem.
2. Hard to diagnose.
3. Same here.

Fix it:

First step: - post your system information here, as requested in the sticked thread at the top of these forums: Must read before posting: How to post your System/Network information (which, despite it's location and name ... not many people actually read). Don't worry the information will need to be split over a few posts due to the size limit of individual posts.

That information will tell us the state of your drivers, the date and version of your drivers, the hardware you are running and any programs that may be causing you problems. Even if it seems tedious please post all the info requested in that thread, it will help us help you MUCH faster.

Now on to the actual fixes...

• If your video card is not up to running MxO then I'm afraid the only solution is a better video card. If this is the case then it might be worth checking how "up to it" the rest of your computer is. I'd recommend the fastest CPU you can get and 1GB of RAM as well as a medium-high to high end video card.
• If your DirectX install is damaged, then we tackle that when we know the problem... depending on the damage as to how we should fix it.
• If you video drivers are old and/or busted then you will need to:
  1. uninstall you video card completely (need to know your operating system to tell you how to do this)
  2. run a driver cleaner program that removes the left-over driver files (I recommend DriverCleaner Pro, It works for all major card types and is free)
  3. install the latest video drivers for your card. If you have a destop machine, the drivers can be downloaded from the manufacturers website, if you have a laptop the drivers may have to come from the computer manufacturers website ... depending on the age of the card.

So... post your system's information like David and I have requested and we'll go from there.

Argh! no edit or preview on posts... *steam comes comically from phi's ears*

I also forgot to mention that your first step should be to run a full system check as explained HERE.
It is a two stage process so make sure you do it right.