Best way to reinstall Windows on bootcamp partition?

Hello,

I have a 15" Macbook Pro 2.8GHz from fall 2009 (and I'm still on Snow Leopard), and I currently have a bootcamp partition of 100GB with Windows Vista Business 32 bit installed.

I would like to make a fresh installation of Windows and get Windows 7 instead (32bit Professional, I only have a serial-key for that through my study, the 64 bit is used for my desktop computer).

However, I am not sure about the best method to do this, additionally, I'd like the partition to be a little larger - but if it's troublesome to do this I can skip it and stick with my 100GB partition, it's not a big deal I think.

I was thinking about two different ways to do it:

1. Delete the partition through the bootcamp assistant and start all over (also enabling me to make a larger partition). I have mixed feelings about this though, as I think it sounds a little risky to remove a partition like this without wiping the whole disk?

2. Insert the Windows dvd and boot from it, and then format the bootcamp partition and install Win 7, just as if I was on a PC.

I don't trust upgrading Vista to 7 without doing a fresh install either, so I am hoping that I can do something else without running into problems

It's important for me that I have a stable and good installation of Windows as I will be traveling for some months to study, so my only computer is my laptop - and I'm going to do some resource hungry stuff while in Windows.

I hope someone can advice me, thanks in advance

 

You don't think my second option would work?

Also, did you defragment the drive after removing the bootcamp partition or anything?