I don't know loads about computers so bare with me.
The other day my computer kept giving an error saying on start up saying insert boot device, and the orange light on the front was on. When going into BIOS my SATA hard drive wasn't detected at all.
A friend had a new, working SATA drive laying around that i tested, which also wasn't detected in BIOS.
On the advice of said friend, I tried removing the CMOS battery, then putting it back in. Once the CMOS battery was put back in, and the computer was booted with my friends hard drive hooked up, the hard drive was detected in BIOS. However, 5 minutes later, BIOS stopped detecting the drive.
After fiddling around, and taking out the CMOS battery and putting it back in multiple times I came to the conclusion that BIOS only detects my friends hard drive, on the first start up after the battery is put back in. Any start ups after that result in the drive not being detected. The original drive is never detected, regardless of whether the battery has been taken out or not.
The BIOS battery remove / replace step is only the first of three steps. To reset your BIOS you do:
1. Power off and disconnect the power cord. Open case and remove the quarter-sized battery from its mobo holder. Find the mobo pins for BIOS Reset. Move the jumper on the pins to the Reset position for 5-10 sec, then return the jumper to its storage position. Replace the battery. Close case, reconnect power cord.
2. Turn on and go immediately into BIOS Setup. Go to the screens that allow you to Load Default settings. Load either Factory Default, or better Optimized Factory Defaults settings. IF you KNOW that some settings were customized, change them. For example, at least verify that your HDD ports are Enabled and the SATA port mode settings are right. Make sure your Boot Priority Sequence is set - probably use the optical drive first, the correct SATA drive second, and NO other options after that. If you know you had custom settings for CPU or RAM voltages or timings, set those. Otherwise leave them alone for now.
3. Use the Save and Exit key and the machine will save these BIOS settings and reboot. See if that gives you stable operation.