"If you receive a Windows error citing, "The launcher has experienced an error please restart the application," the easiest, and most likely, resolution to your issue will be to reinstall the game using the reinstall guide in this knowledge base. It is very important than you use the guide to ensure you're obtaining the latest version of our setup files. You should also verify that you have the latest Windows service pack installed on your computer.
- For Windows XP the most recent service pack is SP3
- For Windows XP 64 bit the most recent service pack is SP2
- For Windows Vista the most recent service pack is SP2
Other causes of these errors are usually corrupt setup files, either from downloads or files on a CD. Re-downloading and reinstalling League of Legends may solve the issue, but the problem may also be related to bad hardware (motherboard, hard drives, and RAM problems are common).
If you feel the errors are occurring for other reasons not mentioned, please send an email to email@example.com and include a dxdiag as well as your patcher_lib.log. Riot would very much like to gather information from you to improve the patching system."
I have done all the other solutions reinstalled twice redownloaded twice and reinstalled Windows XP SP3, I have also updated framework and directx, please help me with a solution as I get the error message whenever I open the launcher, before last nights patch I was able to log in and play with no errors. By the looks of things I'm not the only one with this problem. Please help thankyou.