Howdy,

There are a few things here...

1. Did your friend check for BIOS updates when he built the new computer? It's something that people commonly forget to do, and it's commonly the cause of problems like this.

2. Check to see if the NIC is allowed to resume the computer. Nihil touched on this, but there are a couple of ways to do it.
--> Disable WOL (Wake-On-Lan) in the BIOS
--> Inside Windows --> Device Manager --> NIC --> Properties --> Power Management --> Ensure that the box "Allow this device to turn on the computer" is not checked.

3. Lastly, it could be due to a BIOS/OS "Resume on error" setting. You can check for any errors by running 'perfmon /rel'.