Drmclien.dll Was Not Found

Virus Removal
DrmClien.dll is a Digital Rights Management file that is used as a form of copy protection. Because it is possible the file was damaged by malware, start by scanning your computer for viruses. Use whatever anti-virus you already have on your system, making sure to click 'Update' before running the scan. Once the results no longer detect any suspicious files, you can proceed. If you do not remove the viruses or spyware first, the problem could return due to the infection.
System Restore
System Restore returns your systems to an earlier state. Because Drmclien.dll is a system file, System Restore will replace it with an older version, hopefully one that isn't damaged. Search for 'System Restore' in the Start menu and choose 'Recommended Restore' to chose the most recent restore point. If you know when the problem first began, pick 'Choose a Different Restore Point' and select the appropriate date from the list. Confirm your selections and System Restore will restart your computer when the process is complete.
System File Checker
The System File Checker takes things a step further by checking and replacing system files with their original versions. Whether Drmclien.dll is missing or damaged, the SFC should be able to replace it. Launch the command prompt from 'Start | All Programs | Accessories | Command Prompt' and type 'sfc /scannow.' Press 'Enter' and wait while it processes. Restart your computer to make sure all changes take effect.
Alternative Methods
Some websites claim to offer Drmclien.dll replacement files that you can download and save in 'C/Windows/System32.' The problem with this is that you have no guarantee of the file's authenticity or compatibility with your system. The file is also stored on your Windows disc if you have one, but takes a bit of manipulating to access it. Instead, install the update for Windows Media Digital Rights Management from Microsoft Support (see Resources.) The update adds new integrity checks, including a replacement for Drmclien.dll that is installed automatically. From the support page, click the link under 'Windows Media Format 9.5 Runtime' to install the update.