Many thanks for your replies.

I'm trying both;
"flasher-3.5 -F RX-51_2009SE_10.2010.19-1.002_PR_COMBINED_002_ARM.bin -f –R"
and
"flasher-3.5 -F RX-51_2009SE_2.2009.51-1_PR_COMBINED_MR0_ARM.bin -f –R"

Removed the "R"
On Vistas 64bit with disabled driver signing, I get: "Image 'secondary', size 109440 bytes
Valid for RX-51: 2601, 2602, 2603
Version 1.4.14.8+0m5
Suitable USB device not found, waiting."

On Vista 32bit something different happened this time, all seemed to be working but in a second command window that came up by itself and scanned to the end stating flashing successful..., than disappeared BUT the N900 didn't restart on its own, any advise?