vsix - Start.process does not work with VSIXInstaller.exe arguments C# -

i trying run process uninstall vs extension on quite mode , seems arguments won't pass.

string vsixinstallerpath = (string)registry.getvalue(@"hkey_current_user\software\microsoft\visualstudio\11.0_config", "vsixinstallerlocation", null);           process uninstallvspackage = new process();           uninstallvspackage = process.start(vsixinstallerpath + " " + (@"/u:guid /quiet")); 

and error get:

the system cannot find file specified

when run command prompts work.

to execute command arguments, have use process.start(string filename, string argument) overload , pass arguments second parameters.

uninstallvspackage = process.start(vsixinstallerpath, "/u:guid /quiet");