I upgraded both my desktop and my laptop(clean install) to 10.10 64 bit.
What I noticed is that usually it happens when there's sound on (music/vlc/youtube/mame) i hear the last second of sound repeated 3 times then my laptop crashes.And I have to force shutdown.

This ONLY happens with 10.10 i reinstalled 10.04 and went back and fourth several times to make sure.

specs:
AMD Athlon(tm) II Dual-Core M300
4 GIGs of ram
ATI M880G mobility Radeon HD 4200