Tin foil on the modem? I would not recommend that without reading the recommendation first. At first blush it would cause the modem to retain heat.
About Windows 10, create an image of your hard drive and then do the update. That way if you do not like Windows 10 you will be able to roll it back. Eventually you will have to update to it. Microsoft is abandoning its current OS scheme and going with one that looks more like the update scheme that Mac uses. After the Windows 10 release, all you will ever get is updates and new features. At this point in time there will never be another version of windows released.