After three posts you should be able to PM...
Try Gábor again...
But I see that, although you joined two years ago, you have only posted here recently.
I assume you have been using the SCF PluginStore's dialog on various SketchUp versions and computers.
Have you downloaded Plugins from SCF ?
Your original user-id etc might have lapsed as the servers were changed about the time you registered.
So you might have lost your earlier user-id for the SCF PluginStore ?
When you use the PluginStore, it submits your currently installed/downloaded for that version and computer to the server and it's stored with your account details, against your-id.
Obviously your replaced computer no longer has your locally-stored user-details.
But there might be something stored against your user-id server-side.
Gábor can advise...