It's the most outrageous, sneaky, aggressive, unruly program I've ever dealt with, in my 20 years of working with computers. It insists on running continuously, answering all calls, and disregarding the will of its owner, no matter what! I'm running it on WinXP. I've tried everything: reconfigured the program, went to MSConfig and unchecked the start-up of WinFax, but to no avail: It comes back and keeps running in the background,no matter what. I've finally outsmarted the program in a sense that it no longer answers all calls: by setting "answer after 50 calls", so I can answer the phone before this monster called Winfax 10 does. But I've never seen a program that has such a hostile mind of its own and runs in the background even when configured not to run. Also, it is stuffed with unneeded complexities, which are designed only to make your simple business of sending and receiving faxes a nightmare!