I want to download the 10.6.8 combo update but every time I try it, my computer just shuts down. Does anybody know how to fix this problem? I am currently using 10.6. I had been using 10.6.8 but i tried to update it thinking that I was using 10.5.8. after installing the 10.6 I realized my mistake. I am using the combo update from Apple but just before that I tried updating my computer to Core Lion from Softonic because Core Lion doesn't exist in the apple store any more and my computer wont support Mountain lion. Now it wont even start up.
Since your Mac doesn't start up anymore, try if you can do an upgrade install from an installation disk. See http://support.apple.com/kb/PH6606. It should keep user files and settings in place, but it often resolves issues like this. If you don't have backups, you can use Disk Utility to save a disk image of the drive to an external drive. See http://support.apple.com/kb/ht1553.
10.6 doesn't have a recovery partition, so you will need to use the older tools for booting and fixing your startup problem.
I tried starting it again later and it started. After I got it started I went to the Apple icon in the top left corner and instead of clicking on software updates I clicked on "about this mac" then I clicked on he software update under the information on which software I was running. It then updated without a problem..