Hey hey! Sorry if this is too late to help, I don't tend to go on my PC at weekends >.< I'm hoping you managed to get it working by now, but if not I can try to help, though, I don't know much help I can be because this project is really old and some people's computers seem to have problems opening it :(
If you're on Mac, I probably can't help at all cos I don't own a Mac to test on >.<
If you're on Windows, you should be able to download either the Solipsism Reigns – GxB – Windows or Solipsism Reigns – GxB – windows (smaller version). Once downloaded, unzip the folder like you usually would by right-clicking it and extracting the files.
Once you've extracted the files to a folder, you should have something that looks like this:
Then you double-click on the exe here:
And the game should run.
BUT, depending on your computer's specs, it could take a looong time to actually do anything >.< On my old laptop, it took something crazy like a full 5-7 minutes to actually launch the game after clicking the exe. It looks like it's not doing anything, but it does eventually open. Unless the computer doesn't have enough memory, then it might just not do anything >.< Even on my PC which has relatively decent specs, it still takes about 20 seconds to actually launch though.
If your folder doesn't look like that after extracting the files though, or if clicking the exe opens up something that isn't the game, then it probably means you're one of the unlucky people who has the weird error that I don't know how to fix T_T