It can be recyled, monitor too (monitors are full of leaded glass—really really recycle them), but you have to find a place that takes e-waste. A lot of non-profits will run e-waste collection specials (at least in California…) watch for signs.
Worst case, there are pseudo-commercial e-waste collection places that will take the stuff for a fee.
If you don’t feel comfortable blanking your own hard drive (it is not entirely trivial), donate it without the hard drive and find a friendly geek to blank the drive for you.