C# Launcher - Making it faster

I currently have a launcher (game updater) coded in C#. The launcher need to be recoded to work ASYNC, it lag when you start it and the design need to be recoded. About 5% of our beta tester who tested it can't use it (can't download xml info) so this need to be checked also 1) Recoding it to be faster 2) Checking and fixing the interface to be faster 3) Checking the problem with failed to get patch info (xml) I actually speak french and english, if you can't speak one of those perfectly, please don't bid. Thank you.