Hello and welcome to justanswer, My name is ***** ***** i will be assisting you today,
I'm sorry about the issue, The ntdll.dll files are files that contains NT kernel functions. is not a spyware, a trojan, or a virus. However, like any file on your computer it can become corrupted by a virus or trojan.
to fix this error, run a full scan using your antivirus, Next, you want to run Malwarebytes, a free malware/virus scanner.
Please click https://www.malwarebytes.org/mwb-download Once you install it, Please Update and then run a Quick Scan and Delete any Malware/Viruses. It should take 20-45 minutes to complete.
restart your computer anc check, if the problem persists make sure drivers on your computer are updated to the current version and available, next download ntdll.dll file from this link : http://www.dll-files.com/dllindex/dll-files.shtml?ntdll download the zip file then unzip it and copy it to c:\windows\system32
Now click start and type cmd, a black box will appear please type : regsvr32 Ntdll.dll and press enter
restart your computer and check.
the third solution that you can use is to download and install speedypc pro registry cleaner from : http://www.speedypc.com/ once you install the program please run a full scan.
if you need further help let me know and i will gladly continue to help