Boxster won't start...

[NUFC3]

Left my '99 boxster on a trickle charge. Then when I went to start it, after it had been sitting for 5 days, nothing. It had been super cold. I Went through the usual checks. Battery is almost new. No blown fuses. Thought it might be the clutch switch, but alas no.

Then I checked the starter relay switch in the trunk. I did that little trick with wire and two male connectors after removing the starter relay. Good news is the car turned over. But she wouldn't fire up. Thought maybe it WAS the starter relay switch so I purchased one from the local dealership. Popped it in today and NOTHING. Car wouldn't even turn over.

I'm not sure what to check next? Any suggestions?