The case i have came with 2 or maybe 3 blue led fans. So the Tomahawk mobo has aRGB,can i plug them into that and i can change the colours,or is it a bad idea?
If they are fixed blue fans then they're probably fixed LEDs that you can't change and powered by either a molex, or a 3 pin. If you have the model number, you can google it to check the connector. From what you have described, I doubt they are compatible with the board's RGB headers.