From your post above, there are several reasons why the ntdll.dll can cause a crash as this.
1) It could be bad hardware or ram.
2) Damaged Windows Files
3) Missing redistributable components
Try #3 first, as it is easiest to fix.
Since you're running 64 Bit Windows 7, download the 64 bit version of Visual Studio 2005 SP1 redistributable Package and install it.
Here is the Link to the 64 bit version:
http://www.microsoft.com/download/en....aspx?id=18471
For others with 32 bit Windows here is the Link:
http://www.microsoft.com/download/en...ang=en&id=5638
Once you download it, click on Run to install the files to your system. You may need to reboot the system after the installation.
Please post back here if this solves Hoster crashing on your computer, so we know. If this does not solve it #1 or #2 should be your fix.
You can also try this FAQ, to see if it may help clean up your computer:
http://www.mtu.com/kb/kb/index.php?a...id=115&relid=1