The hard drive needs to be re-seated if bios is periodically not recognizing the hard disk,
Sometimes due to heat, the heat can make internals expand, then when shut off it contracts which causes things to become loose.
I suggest taking the bottom panel off by unscrewing all the screws and disassembling it.
1. Take out battery and unplug the power source.
2. Unscrew all the necessary screws to remove the bottom panel
- from this point Ground yourself to a Metal object frequently by touching anything metallic in color or conductive, a metal post, wire, or even a doorknob*
- Do not scrub your feet, shoes, socks on the ground, or carpet*
Once finished proceed to step #3
3. Locate the hard drive and unscrew the base screws holding it in
4 *ground yourself*
5 remove the drive gently by sliding it out of the SATA Port.
6 Examine the copper connections of the hard drive's pins, Take a clean rag and damp it with rubbing alcohol and lightly wipe both sides of the pins clean, wait to dry then reconnect the drive by sliding it back in gently into the motherboards SATA port.
7 Make sure its nice and snug and give it a little wiggle, then proceed to put the back cover back on and screw in all the screws.
8 You can now re-insert the battery, then plug it into a power supply,
9 Press the Power button and it should boot and recognize the drive
---Please keep me updated!----