The headhpone issue, maybe is your headphones, you should try other ones. For the clean install I think no matter in what orther do you install the drivers, but for see what are you doing I suggest go for the display driver first
You better go for 9300 or XPS2, the M70 lacks of the new kind of ports as DVI and SD, and there is more expensive just because its tested that it works with "X" programs. I also study architecture and my laptop render fast!, and doesnt heat.
And yes its protable, but alsmot not. I bring my laptop all the week to the collage and let me tell you my legs are strong hehe.
Go for the 9300! but if you have the money go for the XPS2.
EDIT- I use sketchup, autocad, 3d...
Maybe is a Trojan or other nasty program, but in most of the cases is just windows, every time windows try to conection and fails it open a new svchost (as I can remeber my cousin tell me, he is a Sistem Enginner). I dont have any virus or adware or spyware and I have a lot of svchost.exe running.
-EDIT Ah and in windows xp, there is no way you can't stop svchost.exe, is an essential process.
Maybe thats normal, laptops can't handle very well intensive GPU use as a desktop (exept for mobile workstations). If that happend when you are playing an online game, maybe the problem is something else, not the laptop.
Could you be more specific about you laptop specs and what program or game are you using when you got this problem.