which exe decompressor work best for vb6 and vb.net

I have a.dll that Resource Hacker will not open. The message sent back is that the .dll was probably compress with an exe compressor. How do I get around that and Is there a decompressor out there that will display the code with without tearing it up first? As resource Hacker claimed you could read the code in its complied state and decomplied formats. How can it do that?

Thread moved from UtilityBank forum, which is for working programs rather than questions

edit: I have also deleted the duplicates of this thread - please only post a question once.