Hi Andy,

Based on my understanding, you want to lauch a winform application from a
web service's web method, with Process.Start method.

Actually, this issue has been discussed ever in the newsgroup, please refer
to(take care of the line break):
http://groups.google.com/groups?hl=zh-CN&lr=&c2coff=1&frame=right&th=7f0fe4a
94ad546e5&seekm=uqBOOaZQDHA.1712%40TK2MSFTNGP12.phx.gbl

Generally, webservice is not intended for GUI sub system, and maybe runing
in another winstation, so the winform you are invoking will not show out as
expected.

Hope this information helps you.
====================================
Thank you for your patience and cooperation. If you have any questions or
concerns, please feel free to post it in the group. I am standing by to be
of assistance.

Best regards,
Jeffrey Tan
Microsoft Online Partner Support