Hi,
Thank you for writing in Microsoft Communities. I understand that you are unable to open msconfig on the computer.
I understand how frustrating it could be when things do not work as expected. Please do not worry I will try my best to resolve it.
1. Which operating system is installed on your computer?
2. Were there any recent changes made to the computer prior to the issue?
Please go ahead and follow the methods mentioned and later update us on the status of the issue.
Method 1: Run [System File Checker] SFC scan on the computer which would scan for corrupt system files on the computer and replace them.
For Windows 7 and Vista: http://support.microsoft.com/kb/929833
For Windows XP:http://support.microsoft.com/kb/310747
Method 2: Also try to scan your computer from Microsoft Safety Scanner, which would help us to get rid of viruses, spyware, and other malicious software.
The Microsoft Safety Scanner is a free downloadable security tool that provides on-demand scanning and helps remove viruses, spyware, and other malicious software. It works with your existing antivirus software.
http://www.microsoft.com/security/scanner/en-us/default.aspx
Note: The Microsoft Safety Scanner expires 10 days after being downloaded. To rerun a scan with the latest anti-malware definitions, download and run the Microsoft Safety Scanner again.
Note: Any data files that are infected may only be cleaned by deleting the file entirely, which means there is a potential for data loss.
Please perform these recommended steps and post back if you are still experiencing the issue.