^its not his wireless since he said all other devices are working with the wireless
i had a laptop with vista before and it always cause disconnects and sometimes doesn't connect until i disable the wireless and re-enable it. I think its just a vista program
If vista can run on your laptop fine, windows 7 will be fine to install onto the laptop.
Depends on where your computer is from the router and if you want to make it look nice, you can run a long cat5e cable for cheap.