If you are in the market for a new computer and would like to know the differences between a prebuilt computer and a custom built computer there are a couple pros and cons that should be considered.

Advantages of Prebuilt:

Price: Usually a prebuilt computer is slightly less expensive.
Software: Usually a prebuilt computer has a good amount of software bundled with it.

Disadvantages of a Prebuilt:

Support: Usually a prebuilt computer must be shipped for repair with average 2-4 week turnaround.
Software: Usually a prebuilt computer will come with a good amount of demo software.
Upgradeability: Usually a prebuilt computer includes proprietary hardware and replacement parts are extremely expensive.
Configuration: Usually a prebuilt computer is sold with the customer not being able to make any changes to the configuration.
Quality: Customer has no ability to use higher quality parts. Usually a prebuilt computer is built using cheap generic parts.
Operating System: Usually customer cannot choose which operating system to use.

Advantages of a Superior Custom Built:

Configuration: You have complete control over the parts that are used.
Upgradeability: All Superior Computer systems use the latest and greatest hardware and are completely upgradeable.
Software: All Superior Computer systems come with all the DVD and CD burning tools; Word Processing, Spreadsheet, and Presentation utilities; DVD viewing, Anti-Virus, Anti-Malware, Anti-Spyware programs.  All these programs are included and are full versions.  No demos are included.
Quality: All Superior Computer systems use the highest quality parts with the lowest failure rates. Every component is fully tested in house before it is released.
Operating System: Customers get to choose if they want to use Windows XP, Vista, or Linux.
Support: All Superior Computer systems come with a great warranty (desktops have 3-4 years on parts, laptops have 1-3 years on parts -- Labor is Lifetime on all our custom built systems).
Price: Superior Computers is typically $300 less than the competition with the same parts/warranty and around $100 cheaper than a prebuilt with same Warranty and cheaper parts.

Disadvantages of a Superior Custom Built:

None: Superior Computers will price match just about every system quote -- Part for part, warranty for warranty