Hey guys I have a few questions, please help.

1. What is is the easiest dual boot solution?
2. Is there anyway to set up a dual boot without reinstalling windows 7 without messing with bios?
3. I have an older snow leopard install package from (Hazard I think) is there a way to install mac updates without downloading a new package?
4. Internet, video drivers, and audio are important; is there anyway to make sure those things work from the start?

Here are my specs:

Dell Xps 8100
Intel Core i5-750
4gb ddr ram
Realteck ALC887 (audio drivers)
Radeon HD 3850
Foxconn FITI PID9106 (Card Reader)