You need to insure your case is properly ventilated / has airflow.
Decent cases usually have 2 or 3 case fans.
Use a 'cheap' stock case, add much 'extra' hw and you will have problems.
A decent case will cost some 3* more than a stock case.

"John Corliss" <jcorliss@fake.invalid> wrote in message
news:11l9jlmns1jere5@corp.supernews.com...
> My system is set up with two hard drives and I use XXCopy:
>
> http://www.xxcopy.com/index.htm
>
> to clone one to the other on demand. I do *not* use RAID because I want
> control over when a backup copy is made. Unfortunately, I recently fried
> my main hard drive and had to send it back.
>
> Yesterday, I received the replacement hard drive from Newegg.com and
> have installed it. Since I've now gone through two secondary hard drives
> in what I consider to be short order, it's time to figure out why this
> is happening. Kony (my thanks to you!) and somebody else (sorry, I can't
> find the thread now) suggested that I look into cooling the hard drives.
> This makes a lot of sense to me because they're mounted right on top of
> one another, and when I touch them after running the computer for a
> while, they're both rather warm - bordering on HOT.
>
> Time to cool those puppies.
>
> I've been looking at various fan additions and what I really want to do
> is to blow directly ONTO the hard drives in order to maximize heat
> removal. This, however, will blow dust onto the hard drives and as Kony
> mentioned, "while a drive is sealed, most have a filtered vent hole
> still." This means that dust still has a way into the drive, although
> it's a difficult path. Thus, I would think that it's better to suck air
> away from the drives rather than blow onto them.
>
> Mounting a hard drive in a fan unit that fits into a spare 5.25" bay is
> not an option, because I want to cool both hard drives. However, I'm
> thinking of additionally adding a 5.25" bay mounted case fan in the
> middle bay (I have three) to cool my two DVD drives and provide
> additional case ventilation.
>
> But back to the hard drives, I'd like to find something that will mount
> so as to suck the hot air right off of the hard drives and out of the
> case. I would prefer not to use something that will suck the heat off of
> the hard drives and distribute it into the case, but maybe that
> additional fan in the 5.25" empty bay will render that concern of no
> consequence. Any recommendations?
>
> TIA
>
> --
> Regards from John Corliss