Note: for windows vista only. I don't know about others. Hope fully by the end of this you will be Mapling again! Happy mapling :)
Here are the instructions.
1. Click start menu button
2.Click search
3.In the search box type "cmd"
4.Scrol until you reach a "Application" named "cmd"
5.Right click it and run as administrator
6.Now type "ipconfig/flushdns"
7.After type "netsh winsock reset"
8.It will tell you to restart so restart pc
9.atfer restart locate your maplestory folder
10.select "gamelauncher"
11. this is a manual way to lauch maplestory
12.click play and Enjoy :D