Make sure everything is screwed in. Cliped in doesnt count. I had a pc that worked great, but I never screwed in the hard drives, I just used the 3.5 drive clips and that was fine for normal use. Then I sold it on ebay, and those clips were not enoguh to hold the hard drives in durring shipping, and both hard drives came out and rattled around the insde of the case the whole trip, damaging several components.
I had to pay for all the damages, and it was a hard lesson learned. I just dont want you to make the same mistake.
CompTIA A+, CompTIA Network+, Cisco CCENT, Cisco CCNA Routing & Switching