Windows Agent is in a SRVC_DOWN state and does not generate an AgentService<timestamp>.log file when AgentService debugging is enabled. However, you do get an AgentServices.log with an AWSPAWNNT error similar to this:
AWSPAWNNT pid 3556:de4
Spawned process with ID 3240 ca8
In Applications Manager v8.0 before SP10, Java 1.7 is not supported (See KB0140907 for additional details about AM v8.0 and Java 1.7 support).
You must have Java 1.6 installed on the Windows machine. If Java 1.7 exists, it must be uninstalled and replaced with Java 1.6.