Check the driver of your graphic card, and update it before trying anything else. This is the major cause for erratic behaviors.
Check again for the latest driver!
Go in the advanced properties of the Display, and remove all accelerations. Run again Cartool, if it works, the problem is definitely on the graphic card side! (see points 1 and 2).
The graphic card has to be OpenGL compliant, but even if it says so, each manufacturer has its own interpretation of the standard. So try to tune the display setting in the advanced properties. Usually, I recommend setting things for "Fast" rather than "Quality" performances, or something like "Application preferences".
Still it may not work properly, although it works on other computers, then you really have a problem! Either wait for the next driver (points 1, 2, 3), especially if you card is brand new. Or you simply need to change the graphic card, and it is worth putting a little extra money on it. The more it accelerates features by hardware, the better. You can also keep the card when upgrading/changing your PC.
If you don't have an accelerated card, that means you rely on the software library provided in Windows (opengl32.dll). It does behave strangely with demanding applications like Cartool, and especially if you are running short of memory. I can't do anything for you, apart from telling you again to buy a graphic card.
In Cartool, go in Help|About, and see if Cartool recognizes the graphic adapter. If not, it may not be installed correctly (drivers...) or it may be turned off (display settings again).
Try to tune up the properties of the OpenGL. It may change from card to card, but try to remove any anti-aliasing, and select for speed, not quality.
Cartool is not really tuned for printing, though it has the ability. Unfortunately, the Microsoft implementation of OpenGL is known to be buggy, and can not print correctly. To bypass this, do some "copy as bitmaps" and paste in some application, then print. Sorry, that's all for now, I will fix this later.
Make sure you are using the 64bit edition of Cartool, which is highly optimized for speed, and not some old 32bit version.
You must have enough memory to avoid as much as possible memory swapping on the disk. The more the memory, the better, especially if you work with big volumes. Minimum is 512M, I'd say, 1G is fine for now.
Try to optimize the swap file (known as page file in windows), either with some third party utility, or using the following trick. Set page file to 0 (control panel / system / advanced / performance options), ignoring warning messages, reboot, then defrag your disk. Set back the page file to its original amount, reboot again. This will provide a fresh, unfragmented page file, which can really boost your machine again!
It may not be very efficient to have multiple instances of Cartool running at the same time, though it works.
Presently, you must have Administrator rights to run Cartool, because it updates the Windows registry. If it is not the case, try this. Do a shortcut to Cartool.exe on the desktop, and edit its properties. In the Target field, after the Cartool.exe, add /noregister to avoid touching the registry. Then use this shortcut to launch Cartool. Note that Cartool has to be run at least once as an Administrator to create the file associations for Windows.
Cartool registers all its known file extensions to Windows, and each time it is run. If you happen to have multiple versions of Cartool on your machine, then each version tries to steal the registry for itself at each run time. You finish with a real mess, and double-clicking may open an unexpected version of Cartool (therefor leading to some misunderstandings and/or errors), or simply does not work anymore. Open the correct Cartool version, then reset the registry .