Computer help needed due to lightening strike
The quality of your protection depends upon how much you are willing to spend upon the surge protection devices. There is no way around that.
If you have a PC, you can open the case and determine the model/manufacturer of the motherboard. From there, you can look up the motherboard specifications and what kind of card slots are available to you. Once you know what kind of motherboard you have and the type of slot for additional cards, you can easily order or pick up an ethernet card. Your ethernet chip(s) on the motherboard are definitely toasted by the surge. You are very lucky that your entire motherboard was not scorched!
Regarding Vista, you can buy an upgrade to go to Windows 7. This process is easy and all of your settings are preserved. There is no need for complete re-formatting of the hard drive and a fresh installation of the operating system unless you want to do so. You will be prompted to download and install any number of drivers for items such as a mouse, keyboard, monitor, etc. before Windows 7 will successfully install.
The Vista to 7 upgrade is the first time Microserf has not forced re-formatting. Sadly, you cannot do this with XP. XP is a decent system that many corporations still run. Changeovers from XP to 7 require re-formatting.
Should you decide to do the upgrade from Vista to 7, please back up any critical files either on DVD or with an inexpensive external hard drive.
Good luck!