Q: why does my mac pro keep restarting itself

Crashing? power? You might want to include more about mac model and its configuration that just Mac Pro w/ ML.

2008 3,1 model?

Any kernel panics in the logs?

HT2546- Mac OS X: How to log a kernel panic

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?

Thanks

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

Isolating issues in Mac OS X

Creating a temporary user to isolate user-specific problems:

Isolating an issue by using another user account

Identifying resource hogs and other tips:

Using Activity Monitor to read System Memory and determine how much RAM is being used

Starting the computer in "safe mode":

Mac OS X: What is Safe Boot, Safe Mode?

To identify potential hardware problems:

Apple Hardware Test

General Mac maintenance:

Tips to keep your Mac in top form

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.

About Mac OS X Kernel Panics:

http://support.apple.com/kb/TS3742

Resolving Kernal Panics

http://www.thexlab.com/faqs/kernelpanics.html

http://reviews.cnet.com/8301-13727_7-10344626-263.html

http://macs.about.com/od/usingyourmac/qt/Troubleshooting-Os-X-Kernel-Panics.htm

http://support.apple.com/kb/TS3742

MacBook Series Forums

https://discussions.apple.com/community/notebooks?view=discussions

http://www.apple.com/support/macbookpro

Recovery Mode

http://support.apple.com/kb/HT4718

TimeMachine 101

https://support.apple.com/kb/HT1427

http://www.apple.com/support/timemachine

Mac OS X & Mountain Lion Community

https://discussions.apple.com/community/mac_os

https://discussions.apple.com/community/mac_os/os_x_mountain_lion?view=discussio ns