>> Vista so that can't be altered i understand.
It can - despite Vista supposed to be self tuning I have found that it doesnt pick up the MTU correctly.
I had a problem with my Vista machine running slower than it should be and although there is something else going on with mine, I tweaked my MTU setting since vista wasnt picking up like it should that my router is set at 1430.
I started to write a tutorial a couple of weeks ago about vista and MTU but unfortunately I never got around to finishing it properly as I also wanted to talk about the RWIN.
Anyhow if it helps theres details how to change details on Vista so far here
http://www.kitz.co.uk/adsl/vistaMTU.htmThere's also another way you can get to the cmd prompt and thats via the start > prog files listing..
that I need to also add in. (as well as finish off the rwin stuff)