Updating new drives and disabling integrated graphics

Hello, I will have to deal with a couple of software issues soon and im unsure of how to handle them.

First off Im placing an aftermarket gpu on amb that already has an integrated gpu on it. I know that I have to disable the onboard gpu but how do I go about it? Is it simply done via bios?

Secondly, im building a pc from scratch but im recycling the harddisk because I dont see the point in buying a new one given that im ditching my old pc and the old harddrive will go unused. Anyways, the old disk contains info. regarding the old motherboard as well as the integrated graphics on it. How do I go about it? Do i need to remove the old mb/gpu drive files or can I get by with simply sticking the old disk on the new desk?

I suppose that Im also going to be needing to install/ update a lot of drivers. Would it be okay to go ahead and install the drivers that come on the cd ( until I can get my hands on the latest drivers) or should I go straight ahead and download the lastest drives from the site?

I did most of the wiring today and I should be recieving the cpu, gpu and ram tomorrow. I suppose that it is okay to have messy cabling atm but once I get going I should have some sort of organization. Im having trouble separating the cables mainly because the psu cables are very tough and arent very flexible. I tried to separate cables as much as I could today but I always ended up grouping the psu cables with the fans/ other small wires.

Also would there be any problems if I was to saturate the 4 pin power cables with the fan cables? I have 7 fans and I was barely able to find a plug for all of them.

Sorry about mixing up the questions in a single thread. I dont want to have threads or all over.

Any help will be appreciated,

Thanks in advance.