Dell :: 64 Bit Upgrade And Sound

I received my studio 17 (p8400, 4 GB, ati 3650) 2 weeks ago and I love it. However theres a few things I wan't to change such as 32bit to 64bit. I thought it would be very simple but i realised there is a lot more to it (or not).

Forgive me if some questions have been answered before and if they seem obvious.

1.) I have read the 32 bit vista is useable on the 64 bit of the same type of vista correct? This would mean I could just use my 64 bit vista DVD to install and use my current Dell CD Vista key with it?

Or would I be best off asking a copy from dell as it may come with all the dell apps with it not that I would need them.

2.) Would installing using my own disk void warranty rather than using dells requested DVD?

3.) Also if I upgrade to 64 bit would this effect the recovery partition. Eg. Would I just be able to format the C: partition, Install 64bit vista on that and leave the D: Recovery partiton alone. Th reason I ask is I read removing this may lead to void of warranty which I wouldnt as im only 2 weeks into.

Sound Issue

I find that the sound can be distorted on just medium level. I have tried a lot of solutions such as installing new drivers, getting rid of IDT drivers and using the default windows ones. I have a wifi 5100 intel card so the other solution provided does not apply to me. However this is not a big issue to me as I can use headphones but would be nice to have them working normally. I also think it could be just a faulty speaker as one side seems more distorted.