Hey guys, I purchased some parts from OcUK last week.
Had the system running for a few days and I'm pleased with the build. However, the system appears to shut down at random intervals without any warning or error message. Is there any way I can determine whether it is an issue with the PSU without buying another unit? I'm hoping that it is a software issue rather than a component issue. 
Using XP if that is any help.
Thank you for your time.
Code:
AMD Athlon II X4 Quad Core 635 2.90GHz (Socket AM3) - Retail 1
Patriot Viper 4GB (2x2GB) PC3-10666 1333MHz Dual Channel (PVS34G1333ELK) 1
Asus M4A78LT-M LE AMD 760G (Socket AM3) DDR3 Motherboard 1
Corsair CX 400W ATX Power Supply (CMPSU-400CXUK) 1
Seagate Barracuda 7200.12 500GB SATA-II 16MB Cache - OEM (ST3500418AS) 1
Xigmatek Asgard Midi Tower Case - Black 1
Samsung SH-S223C/BEBE 22x DVDąRW SATA ReWriter (Black) - OEM 1

Using XP if that is any help.
Thank you for your time.