PC shuts down with usb sandisk

I built PC with MSI VIA chipset M/B & 700MHZ Pentium III CPU. After booting to post PC shuts down with usb card reader plugged in. Unplug card reader and it usually starts normally. I”ve tried new power supply, different card reader, new memory, new hard drive and video card. Sometimes developes cross-linked files after shutting down.