What do you mean?
If your mac is loading slow on startup, it is most likelyto do with its SSD; so I'd recommend getting that checked out, or clearing up some space :)
http://www.ofzenandcomputing.com/fix-mac-blue-screen-boot/
to fix the everlasting loading screen on the R4 DS, get an earlier version of the software. I found a file called English-1.12 which when loaded fixes the loading problem.
you reformat it
holding down the power button for an extended period of time
coco nuts
Try using special utility - Rundll Fix Wizard as I remember. Scan your PC for viruses also.
Have you tried deleting your addons?
To change the screen resolution on a mac:Open system preferences by:clicking the apple menu at the top of the screen, then clicking on system preferencesClick on displaysHere, you will find all of the screen resolution settings that your Mac can support.
Macs don't get the Blue screen of death. Only Windows 95 to Windows 7
The fix could be that you are using the wrong startup disk. When you turn your PC or mac on press f1 repeatedly until you come to the startup menu. From this select 'startup' preferences, start up disk and select the right one. If you are unsure there is no harm in trying them all as i doubt you will have more than 2 hard disks.
On much older Macs, the Sad Mac screen means the POST (power-on self test) has failed, and therefore something has gone severely wrong, and is usually either not possible to fix or not worth it because of cost. It's also often hardware-related, which means you would actually have to open up your computer to fix it. If you want to know exactly what went wrong, the sad mac screen comes with a hexadecimal error code that you can look up to figure out what happened. (for example, something inside your computer came loose and no longer works) That, or you interrupted the startup sequence, which would just require a restart. Keep in mind this problem only exists on very old Macs (Macs without USB ports) so if it's newer than that, you're probably misinterpreting what the Sad Mac screen is.
you cant