B767 First Officer reports unstabilized VOR approach after VNAV is selected at the FAF with Flaps 5. Thrust increase occured at VNAV selection and attempts to salvage the approach are unsuccessful resulting in a go-around.

Narrative

Runway 6/24 is being resurfaced at BDL. It is unusable. Runway 15 was in use due to winds (200/14). We set up for and the Captain briefed for a visual approach backed up with the VOR 15. I entered the speeds into the CDU and the Captain verified that they were correct. Approaching the final approach fix with altitude hold the Captain called for the minimums altitude (1300) to be set in the MCP and I set it. We were still at Flaps 5. When we intercepted the VNAV path the Captain selected VNAV; the thrust levers came way up and we pitched up. The Captain punched off the autopilot and autothrottles and pitched down to try to get back on path. He called for Flaps 20 and also extended the speed brakes. We were still too fast for Flaps 30 and could not slow down and go down at the same time. When I started thinking that this wasn't going to work we got a GPWS warning; probably for terrain closure rate; and the Captain called for and executed a go-around. I think this occurred around 700 AGL. We did the go-around and got vectored for another visual approach with an uneventful landing on Runway 15. What went wrong? Runway 15 is a fairly short runway with a fairly steep approach to it. We should have been fully configured; on speed and at FAF altitude at the FAF. We weren't and I didn't speak up about it. It all seemed manageable until the captain selected VNAV and the throttles came up and we got off path. I don't know why that happened. I believe all our MCP and CDU settings were correct. So we were not configured; high and fast and fighting to get back on path. At 1000 FT I should have strongly suggested a go-around because we obviously weren't stable. I was a couple of steps behind and we got the GPWS warning first.