Are you able to repair a Mac

In order to fix your Mac PC, we need to determine what the problem is. You did not define the reason why you need to fix your PC. If you are encountering start-up problems, it may be related to power supply, battery, hard drive, corrupted OS or user account issue. Does your Mac PC turn on? Does it make noises? Or has blinking lights? If you are an advanced user with knowledge on fixing a Mac PC, then it is possible not to bring it to any computer repair shop. But if you know only the basic troubleshooting, I suggest not to touch anything on your PC or it may cause harm or additional problems or issues.

Dear Chris,

Of course you can open your Mac Pro desktop computer, that's it unless you will void any available warranty. You should  check that before committing to the following. I don't know what your problem is because you haven't stated it in the question so I'll assume you'll know what to do after getting it open.

Now for the opening part:

• Shut down your Mac Pro
• Give it a few minutes to cool down
• Remove all the cables
• Locate the latch on the back of the case
• Pull it out
• The latch lifts out very easily and stops after an inch or two
• Opening this latch releases the side-panel of your Mac Pro
• Lift the panel easily away from the case, take it out and put it in a safe place

You're done, the Mac Pro is now open and you can fix whatever needs fixing.

I hope this helps.