Hi have a MAC Pro 15 inch Mid 2010
I am experiencing the same issues that I see here.
It randlomly shuts down and reboots
It seems to be a related issue that others are experiencing everywhere.
What can be done other than take this in for repair?
I rely on my computer for my business.
Can it be repaired on the spot without losing the use of my MAC for days?
There are hundreds of reasons it could be crashing and/or restarting. Post a kernel panic log (if there are any) for readers to analyze and possibly determine the cause of the restart.
Otherwise, make an appointment at the genius bar (FREE) and they will use their diagnostics to check for Hardware problems. Whether it even needs repair or whether they (or you) can repair it on the spot depends on the specific problem.
I tried to get your post moved to the MacBook Pro forum where others with your model and experience.
Pulling answers out of a rabbit's hat is magic. Diagnosing anything is trial and error and starting from scratch.
If it is for business, you should have multiple booable backup copies of your system so you can work from another hard drive.
I keep a spare computer handy if one of them runs into trouble.
General purpose Mac troubleshooting guide:
Mac OS X: Starting up in Safe Mode - http://docs.info.apple.com/article.html?artnum=107393
What is Safe Boot, Safe Mode? (Mac OS X) - http://support.apple.com/kb/HT1564
Creating a temporary user to isolate user-specific problems:
Identifying resource hogs and other tips:
Starting the computer in "safe mode":
To identify potential hardware problems:
General Mac maintenance:
How to install OS X on a new or faulty HD without Internet recovery
Corrupt and new disks might not have a working Recovery partition, but there are still ways to access one and reinstall OS X, if needed.http://reviews.cnet.com/8301-13727_7-57594422-263/how-to-install-os-x-on-a-new-o r-faulty-hd-without-internet-recovery/
About Mac OS X Kernel Panics:
Resolving Kernal Panics
MacBook Series Forums
Mac OS X & Mountain Lion Community