Are you using a fieldpoint controller or a fieldpoint network module?
You are asking about whether a PC loses power. But is your concern about when the controller or network module loses power?
If the PC loses power but not the controller/network module, then all the outputs should remain at their last good value. Basically you've removed any communication providing data updates.
If the controller/network module loses power, then all I/O modules would lose power. But if the power comes back, then the I/O modules would go to their default startup state until the PC would communicate a new value to them.
You should also look at the watchdog functions. I know a fieldpoint controller has them, but I haven't worked with a network module.
As Thoric said, if it is critical for safety, then the PC and/or fieldpoint controller/module should be backed up with a UPS. Factor in some code so that it can detect the loss of power and set all values and outputs in your system to safe settings before the UPS system's battery would die.
