Kyle Guzman wrote in :

Does any one know what will happen if you reistall
steam, will it delete your friends list ??

It should not, I believe your friends list is stored online.

You can go to http://www.steamcommunities.com and login to your steam
accoun there, you should see all your friends listed there.

Try it from a different system if you're really worried, but as I recall
the Friends list is stored online, not on your computer.

--
-A.