I bought an Asus R7 240 2GB and as I mentioned in title it takes 25 seconds to show BIOS POST screen. Here's my computer's specs:
Asus M2N68-AM SE2 Motherboard
AMD Athlon II X4 620 Overclocked at 2.82 GHz from 2.61 GHz
DDR2 800 MHz 2x2 RAM
AMD Asus R7 240 2 GB DDR3 Graphics card
ZALMAN ZM-400 LE 400W PSU.
I've been suffering this problem since I bought this card in August 2014. I will appreciate every help.