Hi again Asp and also sorry to hear from you again!!
I've just replied to your email, but it does sound like the Southbridge chip has become unsoldered. This is becoming quite a common problem on T43's but a reflow / reball will fix it.
Also we usually see either only the USB or HDD not working with everything else fine, but have also seen the keyboard also not working.
I did have a pictorial diagram of how the different parts of the SB chip are assigned, and the various functions are grouped together. I guess the USB and HDD parts are just more suseptible to failure than the rest.
Anyway it's good to have a UK fan club of people who actually want their laptops to fail repeatedly so they can send it to me!!! Maybe we could see how many different faults one laptop can have and still be fixed...
For everyone else's information Asp's laptop's previous problem were blown motherboard fuses (not a reflow which has failed again).