This is a WindowsXP issue. By default, Windows XP does not allow the PC to go to S3 standby (fans off) if there is a USB device that wants to have the ability to wake the PC. So, instead the PC goes to S1 standby (fans ON). You have one of two options:
1. There is a registry modification which can be made to tell Windows XP to allow the PC to go to S3 standby anyway. For details on this, see:
http://www.usbuirt.com/phpBB2/viewtopic ... light=hack
2. OR, if yo don't need the ability for the USB-UIRT to wake the PC, you can turn off this function on the USB-UIRT by downloading and running the lrnHelper applet:
www.usbuirt.com/lrnhelper_0_0_3.zip and choosing File->Wake-Up Configuration... and then by un-checking the box for wake-up enable.
Jon