Hey there, XxDaBombGamerxX!
I'd suggest to take out any CDs from your DVD/CD-ROM and check if the humming is still there.
If it is coming from the hard drive, it's definitely not a good sign and I strongly recommend backing up all the data from it.
Afterwards, I suggest you go to your HDD manufacturer's website and download their diagnostics tool to test the drive's health and SMART status data.
It seems as it's coming from the disk drive yet there is no cd
If it is coming from the CD-ROM, I suggest to clean the drive lens, dust them out. I hope that will make the humming go away.
Let me know how it goes!

SuperSoph_WD