More details would be helpful. You said it attempts to open AC. Does this mean that the AC Client actually starts to run? Like, you get the screen with the blue vials but nothing happens? Or does it not ever open up the client.
First thing I'd do is check to make sure the correct files are there. acclient.exe, client_portal.dat, client_cell_1.dat, and the launcher configuration file.
If everything is there, I'd open the launcher config file and make sure application=acclient.exe. On my file GameInstallDirectory=. but setting it to the correct path might be a good idea.
After that I'd check your firewall/security programs to make sure they are letting the client connect.
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An Adventurer - Axe and UA spec warrior - no magic