But i tried both and both didnt work.

I am confused a lot becas as he said, i got the same problem.

Will this be a device fault?

Guys one question for you. Wen i try this as you people said, i got a window opened saying that new hardware found ( which xp does for all devices including ipod and other external devices )
During that process we used to insert a cd and ask the xp to get the drivers needed for it.

Is there anyting tat i need to do like this in this situation ? Becas wen i switch on the nokia during the software upgrade, i get that window along with this. It has even a title NOKIA N800 (UPDATE MODE). When i click the radio button [yes this time only ], then it starts searching and founds nothing. Then on status bar, a problem occured while installing this device.

I am sure this must be noting to do with the nokia software upgrade process right??
Pls someone clarify my doubt.

Or is this the cause for the software upgrade gives the message DEVICE NOT FOUND?