Although Windows 2000 and XP actively go out of there way to protect critical system files, the same cannot be said about Windows 9x/ME. It’s all too easy for a program to be poorly written, and in many cases developers take the terrible step of overwriting system files to meet their own needs – winsock.dll being a common casualty. This often causes problems with other applications that rely on the original Windows versions.
The System File Checker tool is another utility accessible from the System Information tools menu that allows you to scan for any system files that may have been modified or corrupted, perhaps during the installation of a new software package. After opening the tool, choose the option to scan for altered or corrupted files. If any such files are encountered, you will be prompted to restore the original version of the file from the original source files, such as your Windows CD.