LinuxQuestions.org - Frequent system lockups

I set up a 281 frame animation in blender to run overnight.

PROBLEM:
When I came back to it the next morning, the system had these properites, all which weren't there last night.
i) internet is very sluggish
ii) switching between windows is extremely slow
iii) I am unable to switch between desktop window frames
iv) I cannot load any new apps (infitesimally slow response from K menus)
v) I cannot get a response to requests for shutdown.
vi) Only redress is power key.

This problem is preventing my working in linux. If anyone can give me any advice I will be eternally grateful. I appeal to this community for help, as perhaps you've seen this happen before.

FREQUENCY:
It happens:
i) On one box (Aptiva Netvista 2.8 GHz, 512 MB RAM), a box where I once in my foggy recollection saw a MEMTEST failure (but not this week). It can happen no matter what I've done and especially whn I never ran blender.
a) With Knoppix 5.01 (HDD install or live boot) perhaps 40% of the time.
b) With multiple versions of k/edu/ubuntu (HDD install, live boot). Ubuntu being much more egregious-- it happens every time I leave it alone for 1 h.
c) If I remember correctly, "never" with SUSE 10.0 (but the USB response time is unacceptably slow, a feature confirmed by an expert in their forum).
ii) On another box (same model, different year, 1.5GB RAM):
a) With kubuntu 6.01 HDD install just one time, and it's the last straw.

DISTRO SWITCH ?
I am willing to switch distros (again-- I do it about every two weeks) if anyone can assure me that they had hardware that was prone to this type of problem and another distro fixed it. My unnegotiable principles for the distro are:
i) atheros wifi driver built in. (SUSE 10.1 is out)
ii) Rapid, smooth USB connection (SUSE 10.0 is out)
iii) povray and blender (v>2.3) installable form a pacakge management system of some level.
My negotiable principles are:
iii) It ain't from Redmond
iv) free version avail to public on same terms as corporate. (But hey, I'll paypal them some bucks if they have such a high level of hardware competency).
v) live CD.

POSSIBLE ADVICE:
i) Switch distro to _________.
ii) You need to use the magic cheat code set of keystrokes to wake up the system and it is_____.
iii) You need to eschew ever using mode "X" of auto sleep/ auto hibernate / auto standby; eschew screen saver "X". (This advice gets me through my day job on a quirky WinXP laptop).
iv) Re-flash my bios. (A person in my local LUG suggested this, and I'm dubious, but if it were the solution, I'm going Vista).
v) Eschew desktop environment "X".
vi) Switch physical memory.