how do i uninstall and reinstall failing software?

Start with the basics. It is not clear what you want to do and why or what is happening.

This forum is for 65lb towers, not notebooks. Though you may want the Mac OS forum area itself.

Direct you to the proper forum for MacBook :
MacBook Series Forums
https://discussions.apple.com/community/notebooks?view=discussions
http://www.apple.com/support/macbookpro

Mac OS X Forum
https://discussions.apple.com/community/mac_os?view=discussions

Failing software? what are you trying to do and have you used Safe Boot and Recovery Mode.

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

Normally you don't uninstall the application unless it is not compatible.

And I strongly recommend you use a couple types of backups.

Recovery Mode

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

TimeMachine 101

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

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

To uninstall depends on the software installer.

If it had an installer, then you need the uninstaller to remove all the parts. That is usually on the same dmg that you used to install, or it might have been installed onto your Mac by the installer. See the company website to find the uninstaller or the instructions.

If it was Drag and Drop, just drag the app to the Trash.

If it was App Store, go to Launch Pad and hold down the Option key. A small X will appear on the icon. click that.