monitor will not wake up

Ok, my issue is that when my monitor goes into sleep mode it refuses to wake up. I literally have to unplug the monitor, then replug for it to turn back on. And even then it takes about 5-10mins. This is really annoying and I'm hoping someone here can help me. I'm running a dual monitor set-up and the monitor that's the issue is the main one. (HP 2159 [Monitor] (21.7"vis, s/n CNT916Z6N7, April 2009))

A few details about my computer:
Operating System
Windows 7 Ultimate (x64) Service Pack 1 (build 7601)
Install Language: English (United States)
System Locale: English (United States)
Installed: 2/9/2012 4:28:27 PM
Boot Mode: BIOS (Secure Boot not supported)
System Model
Gigabyte Technology Co., Ltd. GA-970A-UD3
Enclosure Type: Desktop
Processor
3.13 gigahertz AMD FX-8120 Eight-Core
256 kilobyte primary memory cache
2048 kilobyte tertiary memory cache
64-bit ready
Multi-core (4 total)
Hyper-threaded (8 total)
Main Circuit Board
Board: Gigabyte Technology Co., Ltd. GA-970A-UD3
Bus Clock: 200 megahertz
BIOS: Award Software International, Inc. F4 10/13/2011
Display
AMD Radeon HD 7700 Series [Display adapter]
HP 2159 [Monitor] (21.7"vis, s/n CNT916Z6N7, April 2009)
Samsung SMB2270HD [Monitor] (21.7"vis, March 2010)