windows 7 - Hard drive not found after blue-screen

I met a blue-screen and then a problem saying "Hard drive not found" when I was re-booting my system. But when I plug the power cable of the hard drive and re-insert it, the system can be successfully booted and can be normally run.

Such problems were met several times, all occurring some time (several days) after normal running of the system. In fact, I have changed the hard drive for that problem. But the new drive still has the old problem. I wonder what is wrong. My system is 64-bit Win7 Enterprise Edition. The hard drive is WDC WD10EALX-759BA1 ATA.