If your license is less that 12 months old, you can download the latest version and install it on your PC.
Their is an option on the license dialog to invalidate the old computer.
If you license is more than 12 months old, you can either upgrade it to the latest version, or send us your license number and we can send yo a link to the most recent version you are allows to use. However, you cannot use older versions with SketchUp 8, because some changes in SketchUp 8 require the latest version of IRender nXt.
The version I have is 3.5 JJ04nxt. It works well in SU 8. When I tried to load I-Render it said that my code was not valid. I have so many I-Render .exe files from past updates that I really don't know which is the correct one any more. I guess I'll need to get a proper link to the right version.
We show that your license was issued in April 2010, so it will be valid for the latest version of IRender nXt.
It should also work with version JJ04. However, you should probably download the latest version when our site comes back up. (Our ISP provider is down for about 30 more minutes, so the download links are not currently working. )
When you get it working, if the license is invalid, click "Report Problem" and send us an email, and we will issue the new authcode manually.
You can also use the "Replace Unused Computer" button to invalidate your old PC, so that you can validate the new one. (None of these things is going to work until the site comes up again)