That laptop should run Windows 7, but first run Windows 7 Upgrade Advisor
to see if any issues are flagged.
The installer is driver
-complete, with any newer drivers
quickly delivered via optional Windows Updates after install. Put your wireless driver on a stick or CD so if it´s needed you can install it and get online quickly to update your drivers. If any drivers are then missing in Device Manager, you can use the Vista drivers on the Dell Support Downloads page for your model here: http://support.dell.com/support/down...&catid=&impid=
I would strongly consider doing a Clean Install to avoid importing corruption from Vista by in-place Upgrading. You can adapt the steps in the Perfect Reinstall link in my signature below to end up with the best possible install.
Let us know if you have any further questions.