Altera/Intel-CycloneII: EP2C35F48C7 - Part Quartus II, Version 9.0 Build 184 04/29/2009 SJ full Version, Service Pack 1 installed, using windows OS(XP)

I am programming our custom board, with usb-blaster, active serial, for an existing project.

I am seeing the Error-

Can't recognize silicon Id for device 1

I have programmed this project( *.pof) and this board several times, succesfully, never encounterd any problem.

We also checked our usb-blaster for loose contacts,,,etc- no luck

In the forum they suggest to check voltage, but I cannot access the board- as it is part of a huge system or no test points to bring out!

Any ideas. let me know please.

thanks,

SR