This error message might come often in computers installed with divx player. This is not a virus or spyware or it will never harm the computer. It often alerts us that the xvidcore.dll is not found. But it has got a major disadvantage it interferes with the quick erasing of the cds or dvds in Nero Express so that the rewrittable drives cannot be read but full erase reverses that error and obviously the videos based on that .dll cannot be played.
We can download that xvidcore.dll from the following link for free
Click here to download
After downloading paste the downloaded .dll in C:\windows\system32