Screen goes dark when I'm on a call

When I make a phone call, the screen goes dark.  If I push the power key, it comes back on but only for a second or two.

Ideas?

Actually, that doesn't work.  Doesn't matter what angle the phone is, the screen goes dark.  I've tried putting it on speaker phone and laying in flat on the desk, holding it in front of me, putting it in the desk cradle, and the screen still goes dark.

Again, the screen goes dark regardless of whether it is in speakerphone or not.  Obviously when I have it in speakerphone mode, I'd prefer it to stay lit, so I can push buttons on the phone or use other apps.  Even when not using the speakerphone, sometimes you need to hit a button on the dialer pad to enter a choice....

This drives me crazy too, but tech support @ Verizon says there's no way to alter this; it does so b/c when you're on a call it is set to where you cannot accidentally disconnect the call.

Juno,

You're 100% correct.  I had Advanced Task Killer installed, and loved how it operated except for the issue with the screen going dark.  So, I use the Task Manager that comes with the phone even though it doesn't "kill" all the apps.

And it's amazing to me the BS that Verizon puts out there as reasons for why things happen.....borders on unethical.  They know damn well that it's not in there intentionally;  gawd.

Just out of curiosity.....do you use free or paid version of advanced task killer?  If you have free version, it won't really affect your phone much because it only kills off background apps; it acts quiet friendly towards core apps.
Here are a few lists of auto killing programs which may hinder the process of core apps.
1. Paid version of Advanced Task Killer
2. Taskiller (Free Version)
3. Taskiller (Paid Version)
4. Memory Booster
There is an app called "Z-Device Test" which you can download it at the market place for free.  It checks up on your phone's hardware throughly, including your proximity sensor.  Just give it a try and see, and let me know with result.  If the result turns out to be ok, then it has to be one of your app that's causing the problem.  If not, your phone is defective.