Troubleshooting a Vista computer system that is having problems can be a difficult task due to the endless software and hardware configuration possibilities on a machine. However, I've put together a basic guide for Vista users that may lend a helping hand in finding out where the trouble lies and how to fix it.

System Restore:

If you do not know where to start and you don't have a clue as to why you're having trouble with Vista, then I recommend using System Restore to take your system files back to a time when you were not having any trouble. To use System Restore, follow the instructions below:

Go to Start>> All Programs>> Accessories>> System Tools>> System Restore
Click Next
Select "Choose a different restore point"
Click Next
Select a date and time that you would like to restore to.
Click Next to begin the process
In the confirmation prompt, select Yes.
Once system restore has completed the process, your computer will restart.

Identify a Hardware Problem:

In this section I will show you how you can identify a hardware problem.

-Memory:

Normally, Vista monitors your installed memory and will notify you when an error occurs. However, for the purpose of troubleshooting it is a good idea to run the Windows Memory Diagnostic Tool manually to rule out a possible memory issue. Here's how:

Go to Start>> Control Panel>> System and Maintenance>> Administrative Tools>> Memory Diagnostic Tool. You may be prompted for an administrators password or confirmation at this point.
Select the option titled: "You can restart your computer and run the tool immediately".
Once the tool has completed the diagnostic process, you will know whether your problem is memory related or not.

-Hard Disk (CHKDSK):

In most cases, problems that develop on a hard disk are from either corrupt system files or physical errors. To identify a possible hard disk problem, you will need to scan your drive for errors. Here's how:

Go to Start>> Computer
Right click the hard disk that you would like to test.
Select Properties
Select the Tools tab
Click the Check Now button under Error-Checking. You may be prompted for an administrators password or confirmation at this point.
Select the option: "Automatically fix file system errors"
Select the option: "Scan for and attempt recovery of bad sectors". Selecting this option will perform a thorough scan of your selected hard disk and attempt to fix any physical errors on the drive. Depending on the size of your hard disk, this could take quite some time to complete. For best results, avoid using your computer system during this process.
Click Start

-Devices:

If you have recently installed a new device on your computer. It is possible that the driver for your device is not compatible with Windows Vista. In most cases, downloading an updated driver from the manufactures web site will solve this problem. If you cannot find an updated driver for your device, try removing the device from your system and see if Vista now boots correctly.

-Software:

Software that was designed to run in Windows XP will usually run fine in Windows Vista. However, some of the older programs will run poorly or not at all. You can try running the Compatibility Wizard to run the program or use the programs Compatibility tab.

If you still cannot get your software to run in the Vista environment, it may be time to find a suitable replacement or if it is that important a program to your business, you still have options:
Dual-boot Vista and the older version of Windows that has ran that program.
Keep an older system that will run that program.

-Vista is running slow:

There are many possible causes and remedies for a Vista system that is running poorly.

-Dual Boot or Multi-boot systems:

If your computer is setup to run two or more operating systems, you can select the boot order so that only one operating system will start when your machine is turned on. Here's how:

Go to Start>> Control Panel>> System and Maintenance>> System
Select Advanced System Settings. You may be prompted for an administrators password or confirmation at this point.
Select the Advanced tab
Select Settings under Startup and Recovery
Under the System startup category you'll find a default operating systems list. Select the operating system that you would like to use when you start your computer.
Click OK and exit all windows.

-Using Startup Repair:

If you are sure that your Vista systems poor performance is not hardware or virus related. You can try running the Startup Repair feature to fix system files that may have become corrupt or gone missing. Here's how:

You will need your Vista installation DVD/CD for this task.
Insert your installation disk
Restart your computer. Your computer should boot to your installation disk. If it won't, you will need to change the boot order in your BIOS. Consult your computer manufactures operating guide for this procedure.

You may receive a prompt asking you to press any key to start Windows from the installation disk.
Select the language setting and then click Next.
Select Repair your computer
Select the operating system that you would like to repair and then click Next.
Select Startup Repair from the System Recovery Options menu.
Follow all of the on-screen prompts and answer the questions accordingly. Your system may restart as repairs are made.
-Using the System File Checker (SFC):

If you are experiencing system lockups or error messages when using Windows applications, you can try running the System File Checker tool to scan your operating system for corrupt files. If the SFC finds any corrupt files, it will automatically replace them with "known" good files. Here's how to use SFC:

Go to Start
In the Serch field, type in: cmd
Right click the "cmd" entry
Select "Run as administrator". Continue through any resulting UAC prompts.
At the command prompt, type in the following command:

sfc /scannow
 
Press Enter on your keyboard
-Using Safe Mode:

Safe Mode is a very useful diagnostic tool used to troubleshoot system startup problems and performance issues. When you start your system in Safe Mode, Vista will run only the basic default Windows settings, services, devices and drivers. If your system performs fine in Safe Mode but poorly in regular mode, you can eliminate these default settings as the cause. You can access Safe Mode by tapping the F8 key on your keyboard as Windows first begins to boot.