And I have no idea what you want us to tell you?
Writing the type of code that can control a fan is not going to be EASY. You need LOTS of experience and some hardware knowledge.
I'm sorry that you obviously have several new and/or small computers that do not have a parallel port. Unfortunately, that makes the task harder to solve.
Joint Technology (HK) Limited - Usb Series
(That was the first link mathcing "usb to i2c" in google).
And then find a I2C compatible fan controller capable of doing PWM on 12V.
I have my USB Experimental Board assembled working with 8 remote electrical plugs (going to expand it to 16 to have more control of my house) and 3 thermometers plus my conditional air (2 rooms).
My current project is a code bar reader in my fridge and its almost finished (i will have control of all my stuff there plus dates so i can have my own reminder of everything stored in fridge)!
My later project will be a system connect a optical and card reader to my computer to use as house security and maybe even conect my alarm sensors to it, hope to have luck with this one!
I would just like to say Thanks to everyone who helped with this simple task, now i know a LOT about how to have my computer communicating with other non-computer hardware!
Once Again, Thanks,