If you really must upgrade, follow the instructions and uninstall the Intel Wireless software from your computer. Then, upon upgrading, you probably won't have to worry about it again. You can search the manufacturer's driver site for Windows 7 or Vista drivers if you desire the Intel software for the wireless card. By removing the Intel application for the wireless card you are giving control of most of the wireless functions back to Windows as opposed to the Intel-designed application (In theory, the Intel wireless software should work better, since Intel created the wireless card.)
If uninstalling the software for the wireless adapter doesn't work, go into Device Manager and remove the wireless card itself by right-clicking and using "Uninstall". Then, initiate the upgrade.
If this is too much trouble follow the above advice and initiate a clean install.
i agree with reghakr, IT IS ALWAYS A MUCH BETTER IDEA TO DO A CLEAN INSTALL INSTEAD OF UPGRADING. i know it is a hassle to reload all of your programs, but it is worth it in the end. i would say to back up all of your important files and folders to an external of some sort, and then bite the bullet and do a clean install. you will be happy that you did, down the road. i guarantee it!