how is your heat sink doing? i had this happen and was shocked (wth - linux crash????) so i was monitering the CPU temp while running the g@h client which seems to be more intensive than the seti@home one, played malestrom, had some xsreensaver demos going and playing mp3s. the cpu temp hit 57 C (hot hot hot!). after a little bit the whole machine locked up. i did get a copper heatsink which has helped (i.e. i have not had anymore lockups) i have an athlon 1200.