Having to boot via install discs again for no apparent reason. Got disc utility via install discs and did repair disc. I got the following report invalid node structure, rebuilding catalog B tree invalid node struture, invalid key length, invalid node structure, the volume macintosh HD could not be repaired Error-the underlying task reported failure on exit 1) HFS volume checked. 1 volume could nor be repaired because of an error Repaired attempted on 1 volume 1 volume could not be repaired. Why has this happened? Thought macs were supposed to be more reliable than the comp hence the higher price. 24 inch iMac 2d2 2.5 yrs old. What's the expected cost of repair UK price? Thanks for any help you may give but not happy as this is the third weekend where it's just given up with the blue screen of death!