Is it possible to get my OS back?

[Zaquery]

Well i CLEANED my HDD with OS and everything off of it with cmd. I then realized that i had no OS, i grabbed my old Flash drive with W7 on it and installed it. After that i couldnt conect to my router wireless nor ethernet. The network controller and ethernet controller drivers didnt install correctly and so i cant get them back because i can not connect to my internet. Please help!

 

[popatim]

If this is a prebuilt system (HP, Dell...) You can contact the manufacturer to purchase restore disks for a nominal fee.
Other than that use the pc you are on to download the correct win7 drivers you need which should be available on the manufacturers website.
If you or someone built the pc then the manufacuterur of your nic would be the motherbd manufacturer or whoever made the add-in card you might be using instead.