How to Unregister the Assembly Registered Using Regasm

I registered one of my dlls on the development machine using regasm as below (ASP application)

In a cmd prompt, I navigated to C:\WINDOWS\Microsoft.NET\Framework\v2.0.50727 and did:

regasm /tlb "xxx.dll"

Now I made some changes in the dll. So I unregistered the dll using the command:

regasm /u xxx.dll /tlb:xxx.tlb

Then I registered the updated dll again with previous command. But the changes are not coming up in the project, so I doubt it's still pointing to the old dll. I restarted the machine, but that did not help. So:

1. What are the ways to make sure my old dll is removed and the current one is new?
2. Is there any physical path to check them manually?

UPDATE: The below solution fixed the issue.

To Register:

SET WorkFolder= '<directory>'
regasm.exe %WorkFolder%\xxx.dll /Codebase

To unregister.

SET WorkFolder= '<directory>'
regasm.exe /unregister %WorkFolder%\xxx.dll