i have a 2010 macbook pro unibody. specs are 2.66ghz c2d, 4gb if that matters. the battery was expanding and pushing up on the trackpad, so i pulled it and threw the machine in a closet. a few weeks later i got a used (but fully operational) battery and tossed it in. yosemite would boot to about 20-25%, then just hang. same behavior for recovery mode, usb installer, etc. i put the hard-drive in another mac, and reinstalled yosemite on it, but it would boot to around 30% and then restart. verbose mode shows it hanging after DSMOS has arrived. i recall from building my hackintosh that the graphics kexts load after DSMOS arrives, so i booted single-user (which works just fine btw) and removed all gfx files from S/L/E now it boots and hangs at 50% i've tried resetting SMC and PRAM in either order any ideas?