If it's a standard two pin fan connector you could try an attenuator to reduce the voltage to the fan and thus the speed at which it rotates. Some fans don't like this. Or, you could simply get a quieter fan - it looks like a 6cm fan to me, these are widely available. Or like the man says, pull the conector out and see if anything melts. I'd love to change that Seagate for a Samsung HA250JC.
I've not got one of these yet (and I never thought I'd even be considering it) but I'm fed up with transfering Wimbledon to my PC for the wife who then doesn't watch it. Easier all round just to give in and make some DVD's for her.
BTW, two points: is the 440 the same as the 540 in all respects apart from HDD size? The Pio web site says there are differences but I also read that they are identical on avforums.
Forgotten what second point was. Doh!