The best resource here seems to be Sony customer services. They would know what Vista driver you need and where to get it.
It might be on their site, it might be on their 'driver and utilities' CD/DVD and it might be that you'll have to use their System Recovery DVD to bring the laptop back to factory conditions.
If you object to the last option they might even be able to email it.
Model: VAIO (Laptop)
Processor: Intel(R) Core(TM)2 Duo CPU 76500 @ 2.10GHz 2.10 GHz
RAM: 4.00 GB
OS: Windows Vista Home Premium
Problem: Where to begin? I tried upgrading from Windows Vista to Windows 7 with the DVD Sony sent me in the mail. Before I could actually begin to install Windows 7, I turned off all system start up items by checking "selective startup" in msconfig. On top of that, an application from Sony started up from the DVD attempting to make sure my computer was ready for the install. It removed "items" from my computer with known issues. After all this, I got 50% into the install only to find that I couldn't finish it because Sony had sent me a faulty disc with corrupt files. I am now awaiting my new disc, but until then I reenabled all the items I had disabled from start up, and have restarted my computer many times since then. My wifi no longer works, the light does not even come on. I can directly connect to the internet via cable, but can no longer use my wifi in classes.
Now everytime I startup my laptop I get a message, "New Hardware Found - Network Controller"... Cool. I'll just install the software and be on my way. Wrong, the computer asks me if I have a CD the Network Controller came with, and im fairly sure I don't. So then I try to find an update online, but can't find one. And on top of that I can't search for a driver update because when I go to "Network Controller -> Properties" the manufacturer is "unknown". However for some reason it keeps taking me to the Intel customer support site to look for an update but never finds one.