I also had the same issue when i first began android developement. My system was old. It didn't even supported Intel's VT technology. If same is the case with you, having a old pc, make an avd with small screen resolution rather than using the tab(Galaxy Nexus). Use something like 'WQVGA' and change the RAM to 1024 MB (if your system has greater than that). then deploy. It worked for me. :)
