The stumbling bloke is the art part of what she uses it for....ideally you want lots of RAM, and ideally quick processor / fast FSB so an Intel chip, at least 1 gig ram. Having a lower spec machine won't stop her using graphics packages at all, just make them a little bit slower (I mess about with photoshop, so don't have a high spec machine, as quite happy to wait an extra second here or their)
What does she use it for / want to use it for in terms of "art."As if this isn't really a factor, any of the cheap laptops are fine for everyday use. The important factors in my mind is, ability to replace battery, good warranty. I am still using a Sony laptop which is a PII 400 with 128mb ram with windows 98....fine for internet / word some photoshop.
Dell do the Inspiron 1501 for £350 ( http://www.dell.co.uk/ ) Don't be fooled by dell telling you are only under warranty for 90 days standard uk sales of goods apply for 1 year (but does not include software screw ups...i.e u get a virus) 2 year warranty £71 (I don't work for dell )
The comet ones start off at £400....
Rgds
Ed