what is dll hell problem?

hello,

Google it! :) These articles might help.

DLL hell
Simplifying Deployment and Solving DLL Hell with the .NET Framework
Strong Names Explained

Strong Key name in .net context is used to secure your dll(s)/exe(s). It is used private/public encryption mechanism to secure our dll. For more details, please bing'ing about the strong key name.

Can keep your any important account open without any sequrity. If yes then no need of strong key name.