Emulators have been driving me crazy for long time because they are so slow. I had no problems
using emulators on android 2.3, 2.2 etc. It takes for ever to load an emulator for android 4.0 and above and most for the time it won't even load. The high resolution you try to you use, the less chance for emulator to start.
I run my emulators on windows 7. Anyway, after a long search, i came a cross this link. http://developer.android.com/tools/devices/emulator.html.
Thanks to intel VM Acceleration for windows. Emulators runs on my laptop in seconds. Its not perfect yet but it does the job. I thought i'd share this, because i wished i knew about it long time ago.
Note: CPU must support one of the following virtualization extensions technologies:
Intel Virtualization Technology (VT, VT-x, vmx) extensions
AMD Virtualization (AMD-V, SVM) extensions (only supported for Linux)
and if it does support VT, remember to enable VT .