FFXIV Crashing and Rebooting PC

Hey there! Been playing FFXIV on my PC since 2.0 came out and have been having a blast. However as of yesterday and today I have experienced hard pc resets while playing FFXIV. This is new to me and I was wondering if anyone else has experienced this too.

I play with medium to high settings, windowed mode, with skype and a web browser running in the back. Would play the game until suddenly I lag, then freeze, then full pc black screen. After a few seconds my pc reboots and I get the "your system unexpectedly crashed" message. No idea whats going on. Hasnt ever been a problem until yesterday. Any help would be appreciated. Thanks!