Stupidly bought a laptop though the home computing initiative 3years ago, finally should finish paying for that this month

(seemed like a good idea at the time when laptops cost a fair bit more than they do now and I didn't have the money to buy one outright)
Its a toshiba satellite p30 series
p4 @ 3.2ghz with HT
1gb ram (2x 512mb)
80gb 7200rpm hdd.
win xp
Dvd rw
64mb 9700 mobility radeon
17" 1400x900 widescreen display
Netgear 54g pcmcia card.
I don't use it (infact i've lent it to my housemate) since I bought a macbook a little over a year ago.
He did at one point want to buy it off me but at the time I said no, but once i've made the final payment then its mine to sell, that's if its actually worth anything now...
Given that you can buy brand new laptops for £300 and dual core ones for ~£400 or less I was thinking of asking for ~100 for it (if he still wants to buy it)
Does this seem resonable?
I know its not much for it But then its a 3year old computer, pretty much worthless thesedays.