Windows 7 Problem accessing networked hard drive

[paul608085]

My home network has a networked hard drive. When I first started using Windows 7, (build 7100), I had no problems mapping it and reconnecting automatically at every logon. Recently, (last month or so), I have found that when I try to map the network drive I get an error: "The account is not authorized to logon from this station". If I tick "Connect using different credentials" and enter my User name and password I can connect OK for that session. I also have a netbook running Windows 7 that has the same problem. PCs running XP SP3 and Linux connect to the networked drive OK.

I assume that this is to do with a security setting that has been changed with an update - can someone point me in the right direction please?

TIA

Paul