Error Stopping TwinCat Runtime

Hi,
After a night of installing and removing programs and drivers. Changing settings everywhere. I finally re-installed my Laptop (WinXPprof). But the problem stays the same: everytime when I stop the TwinCat Runtime the system hangs.
After a call at Beckhoff they told me that this is a known problem with HP and Siemens Laptops. It must be a hardware problem but they have no solution.

Does anybody have an idea what it could be ?

Many thanks and kind regards.

Is is a total lockup or can you use CTRL+ALT+DEL to get into task manager?

If you can then i'd start by loking to see what the CPU usage is (i'd expect it to be 100% if there was a problem), if so then switch view to processes and see what is eating all the system resources, it could be that Twincat Runtime is utilising a memory area thats being used by another application, if that's the case, that proces will be eating up resources (probably) and you'll be able to see it. I've personally never had any major probs with Twincat but i'm not a great fan of it, I always found though that it runs best in Windows2000 opposed to XPpro.

It is a total lockup. Ctrl+Alt+Del is not working anymore.

It may be an issue with the chipset used on that particular laptop, I'm currently running it on a Packard Bell easynote and before that a Sony Vaio, incidentally, what brand and model is your laptop? it may be worth checking for updated drivers for your laptop's mainboard on the manufacturers website, it probably wont work but try running in compatability mode for Windows 2000 see if that makes a difference