Win Vista --> Win 7 upgrade questions

I'm contemplating upgrading my Inspiron 1720 from Windows Vista to Windows 7 with an Upgrade disk. The reason I want to do this is because I have an SSD that I would like to install in the 1720. Win 7 obviously supports TRIM which would be a lot bettter then running Win 7 and watching the SSD die a slow death. My question is this. When installing Win 7 from upgrade media, must I have Win Vista installed at the time? It wouldn't be a problem, more just a PITA. Does it upgrade off my current Vista product key? Are there any known problems that I'm likely to incur in the process? Is my logic or reasoning flawed as far as the SSD issue?

The main reason for this is because I'm going to be getting another M17x and won't need the 1720, but it's still a really good computer. I'm going to be giving it to my brother and I want it to last a few years for him. He doesn't do any gaming, and as you see in the sig, the only bottleneck (after 256GB SSD installation) is the GPU. Which is plenty for his needs. I want the computer to be easy for him to use, (Win7) and not have to go through and do any manual TRIM things. It would never be done. Thus to me Win 7 makes sense. It will minimize my time spent reinstalling everything because his computer is at a crawl.

 

To use the upgrade, you MUST have an OS installed. You can still do a clean install though. The install uses a key, separate to your Windows Vista one; So, you cannot just port it through. I'm unsure about your SSD questions though.

 

My first advice is to read up on the upgrade problems in the Dell forum, if any. Yes you need Vista installed or at least the original disc to install the upgrade. Download the Win7 drivers, if any, at Dell's web site.