I read somewhere that by default the HDD is set to IDE and also we need to make changes in the RAM module settings.
What settings should I make in BIOS to make full use of my hardware?
By default you don't need to do anything. As long as you haven't messed with the BIOS or Windows hardware settings your hard drives should be running at the maximum supported speed/mode and your RAM at the compatible speeds.
For SATA hard drives you can check whether AHCI/RAID is enabled to benefit from NCQ and other features but this is not a "magic setting". The speed gain will be present but not overwhelming.
For the RAM there is potential to overclock but as usual this would be at your own risk and can involve permanently damaging them, the RAM sockets maybe more.
there are some benchmarking tools and you can compare your results with others that have similar configuration.
if your hard drive is IDE then Bios will recognize as IDE, so this is normal.
How to overclock your RAM
before you start messing with the memory. It's much safer to buy more memory than to overclock what you have.
BIOS can detect the RAM settings from the SPD on the memory modules. BIOS has a SPD setting for the memory, this should be used for the highest stability with the computer
overclocking is dangereous since it can peril computer so if you are not expert then better not to adventure in this field unless someone is near of you and knowse how to walk in this stream.
Download CPUZ and click on the 'SPD' (Serial Process Detection) tab. Check your machine's memory specs. Reboot into the BIOS menu and select the performance menu-most likely labeled 'Performance' or 'Configuration', depending on your motherboard manufacturer.
Enter the memory configuration menu, and disable the default memory profile. Adjust your memory multiplier by selecting a preset overclock option or by typing in the RAM clock speed. Use increments, one or two at a time, that match consumer-grade products (DDR3 RAM is 800-1066-1333-1600-1867-2133); save the changes; and exit the BIOS. Stress-test as usual, and consider running memory-testing software such as MemTest.
Wrong BIOS configuration will yield into non bootable WIndows, BIOS are made by the manufacturer so we cant much do with it, and changing voltage values is not recommended. You can change settings like Bios detect your HDD as SATA but should be IDE!
If BIOS dont detect your hardware you will hear Beeps.