I had the same problem after the recent update of microsoft patches i did (windowsupdate.microsoft.com).
It seems the problem on my system is caused by a patch by Microsoft which causes problems with SPTD. It seems this part of the software has problems with the kernel update.
For my system (windows xp x64) the problem is caused by patch :
http://support.microsoft.com/kb/914784
Update for Windows XP x64 Edition (KB914784)
Date last published: 6/13/2006
Install this update to improve Kernel Patch Protection. Kernel patch protection in versions of Windows for x64-based systems protects code and critical structures in the Windows kernel from modification by unknown code or data. After you install this item, you may have to restart your computer.
You can uninstall this patch in c:\windows\$NtUninstallKB914784$\spuninst and run spuninst.exe
I must warn you that it might a security risk to downgrade but hey i want to have my daemon tools running
After rebooting my problem went away.
If someone can find the windows xp version, please reply and try to uninstall that patch and tell us if it does the trick. O it might be handy to look in the uninstalldir of the patch, it should have a ntoskrnl.exe file in it.
To really solve this issue, people need to fix the SPTD to work with the new ntoskrnl.exe.