my mid 2008 imac has run perfectly fine for 6 years. Last year I purchased more RAM (?)-- I am not a computer geek-- and upgraded the operating system, eventually to OS X Mavericks (I think I had to upgrade to snow leopard first, then move on to the lates). Anyhow, I clicked on the "update" button and now I get the gray screen with the apple logo and the "circle". I've been able to get to disk utility ... but I am unable to verify or repair some of the things listed. First line is a picture of a hard drive with: 320.07 BG WDC WD320.... Next line is indented picture of a hard drive with: 6552630 + 652356230 Then a CD looking icon with the word "superdrive" below that. Then further down: Picture of a disk and "Disk 1" indented pictured of hard drive OSX Base System The bottom "OSX Base System" can be verified and no repairs needed. The upper 2 items (320.07 GB.... and 6552630....) cannot be verified completely or repaired. It says "volume repair complete, updating boot support partitions for the volume as requested" in RED. I tried to reinstall OS X Mavericks, but the disks listed (I'm not even sure which one to use, so I tried both listed) say they disks are locked. I tried to use terminal to look at the volumes based on a google search, but so far all terminal prompts come back invalid. I do not have time machine, or back up-- so if there is any way to "repair" or "reinstall" that would be great. At this point, I am in over my head and done trying to figure it out using other peoples questions that are not exactly like mine . . . Any ideas?