Solar panel and little computer fan
Let me make sure I understand. You want to run a fan from a solar panel, while the panel is only illuminated my in incandescent light? This cannot be done. It isn't a matter of voltage regulators or capacitors. The panel simply will not produce enough power to run a normal fan.

It might be possible to run the fan for say 5 seconds every few minutes by storing the power in a cap, but I doubt this is what you want. (BTW, the times stated here are only guesses. The point is you cannot run the fan anywhere close to continuous.)