Scare mongering rubbish.
Sorry mate but if 'every' PC sold by PC World was crap then they would have gone out of business years ago. the build quality is down to the manufacturer and the likes of Packard Bell, Toshiba, etc are decent. Whos to say your mate didn't bounce the PC round in his boot all the way home dislodging the fan.
There are plenty of other mail order/online places as well, pick up a copy of Micro-Mart its full of them.
Onboard graphics again is fine if all you want is a Internet/Office/email. you really don't need 128M gfx for that. Its more important to consider what you want a PC for and then spend the money on the bit that will most influence its perceived performance. I bought a new laptop a couple of weeks ago , I had got it down to a choice of two, one dual core with slightly better gfx chip or a single core, still reasonable gfx but a far nicer screen. I reasoned that I would rarely push the CPU(as 99% of people won't) or play the latest games but I would be looking at the screen a lot. So I went for the better screen as this will improve my perception of its performance.