An assembly display name should include the assembly simple name, version, culture and public key token. The assembly simple name is usually the file name of the assembly without the extension (“.dll” or “.exe”).
For example, the assembly display name for the v1.0 system.dll assembly is:
System, Version=1.0.3300.0, Culture=neutral, PublicKeyToken=b77a5c561934e089
All of those components are required to be specified in calls to Assembly.Load() if the assembly is to be found in the GAC (and I strongly recommend that you always specify them, even if the assembly is not in the GAC).
My plea: please don’t put together these names yourself. Allow Fusion to create them for you so that they will be canonicalized and work with upcoming (and past) versions of Fusion. If you need to get one programmatically, try Assembly.FullName, AssemblyName.FullName, or Type.AssemblyQualifiedName. If you just need to cut-and-paste one into your code, “gacutil /l” is a quick way to get the official string. If you just need the public key/token, try “sn -Tp”.