What's wrong with my HD(s)?

[arachn1d]

I've been using computers my whole life and I've never had a hard drive fail on me before. I guess I'm lucky.
Anyway, while using one of my computers I noticed things weren't really running properly so I restarted as usual – once I restarted I tried to launch some games (it's a hard drive that only has games through steam on it) and it wasn't working. I noticed steam said fatal error and tried to install itself so I'm thinking something is really wrong. I load up "my computer" and I notice "D:/" doesn't exist!
My secondary hard drive is no longer recognized by my computer? I restart the comp and I don't notice any clicking (I recall that is what you listen for on a failed hard drive). Anyway, I restarted a couple times and my computer recognized the HD but I couldn't access anything it in (well I did but then it stopped loading folders after a minute or so). I restarted computer one more time and it didn't recognize hard drive.
I tried replugging it etc and no luck.
So is that a failed HD? Should I just say fk it and buy another?


**update**

So I rebooted again and my second hard drive is there... I'm running a hard drive health monitor and it is saying the hard drive at location 0 (i'm assuming c is at 33% health and my D: is at 70%.... is it somehow reversed? Shouldn't my D be at the lower health or is it my C: drive is causing my D to fail?


** update 2 **

Okay to confirm my C: drive (which is always showing up is at 33% health)
My D: drive which shows up only sometimes is at 76% health.

 

[Dangman]

Download the CD image of Hitachi Drive Fitness Test, burn the ISO file to a CD, and then boot from it, just like you would do with the XP/Vista install CD. Test the hard drive and see if any problems are found. DFT will run on most manufacturers' hard drives. Alternatively, you can use Seagate's SeaTools for DOS to test a Seagate or Maxtor drive. For a Western Digital drive, you could use Data Lifeguard Tools for DOS to test a Western Digital drive.