Switching between multiple versions of a software program

1. A method for switching between multiple copies of a software program on a computer system, the method comprising:

detecting a plurality of copies of the software program on a computer system;

receiving input selecting one of the detected plurality of copies of the software program to be a default copy on the computer system, wherein each copy of the software program in the plurality of copies of the software program is a different version of a same software program, and wherein each of the plurality of copies of the software program are registered with a registry of the computer system such that at a same time each of the copies of the software program is separately identified in the registry of the computer system; and

determining whether the selected copy of the software program is a current default copy on the computer system, wherein if the selected copy of the software program is not the current default copy on the computer system then:

demoting the current default copy to be an alternate copy;

determining one or more features of the current default copy;

ensuring that each of the one or more features no longer exhibits a default interface on the computer system such that only one copy of the software program is operable at any given point in time and other copies, in the plurality of copies of the software program are hidden from users; and

promoting the selected copy of the software program to be a next current default copy, wherein the default copy is a single copy of the software program that presents itself to a user or another computer program as the only copy of the software program on the computer system at any given time.

2. The method of claim 1 , wherein detecting a plurality of copies of the software program comprises looking up a number of versions of the software program that are registered within the registry, wherein each version of the software program corresponds to a copy of the software program.

3. The method of claim 1 , wherein receiving input selecting one of the detected plurality of copies of the software program includes receiving user input selecting one of the detected plurality of copies of the software program.

4. The method of claim 1 , wherein promoting the selected copy of the software program includes determining one or more features of the selected copy of the software program, and ensuring that each of the one or more features exhibits a default interface on the computer system.

5. The method of claim 4 , wherein demoting the current default copy further includes unregistering the current default copy from a registry, and promoting the selected copy of the software program further includes registering the selected copy of the software program in the registry.

6. A computer program product, comprising a computer-readable medium including instructions, for switching between multiple copies of a software program on a computer system, the instructions when executed on a programmable processor cause the programmable processor to:

detect a plurality of copies of the software program on a computer system;

receive input selecting one of the detected plurality of copies of the software program to be a default copy on the computer system, wherein each copy of the software program in the plurality of copies of the software program is a different version of a same software program, and wherein each of the plurality of copies of the software program are registered with a registry of the computer system such that at a same time each of the copies of the software program is separately identified in the registry of the computer system; and

determine whether the selected copy of the software program is a current default copy on the computer system, wherein if the selected copy of the software program is not the current default copy on the computer system then the product further comprises instructions to:

demote the current default copy to be an alternate copy;

determine one or more features of the current default copy;

ensure that each of the one or more features no longer exhibits a default interface on the computer system such that only one copy of the software program is operable at any given point in time and other copies, in the plurality of copies of the software program are hidden from users; and

promote the selected copy of the software program to be a next current default copy, wherein the default copy is a single copy of the software application that presents itself to a user or another computer program as the only copy of the software program on the computer system at any given time.

7. The computer program product of claim 6 , wherein the instructions to detect a plurality of copies of the software program include instructions to look up a number of versions of the software program that are registered within the registry, wherein each version of the software program corresponds to a copy of the software program.

8. The computer program product of claim 6 , wherein the instructions to receive input selecting one of the detected plurality of copies of the software program include instructions to receive user input selecting one of the detected plurality of copies of the software program.

9. The computer program product of claim 6 , wherein the instructions to promote the selected copy of the software program include instructions to determine one or more features of the selected copy of the software program, and ensure that each of the one or more features exhibits a default interface on the computer system.

10. The computer program product of claim 9 , wherein the instructions to demote the current default copy further include instructions to unregister the current default copy from a registry, and the instructions to promote the selected copy of the software program further include instructions to register the selected copy of the software program in the registry.

11. A system for switching between multiple copies of a software program on a computer system, the system comprising:

a global switcher detecting a plurality of copies of the software program on a computer system, receiving input selecting one of the detected plurality of copies of the software program to be a default copy, and determining whether the selected copy of the software program is a current default copy on the computer system,

wherein if the selected copy of the software program is not the current default copy on the computer system then the system further comprises:

a first local switcher demoting the current default copy to be an alternate copy, the first local switcher being associated with the current default copy; and

a second local switcher promoting the selected copy of the software program to be a next current default copy, the second local switcher being associated with the selected copy of the software program, wherein:

each copy of the software program in the plurality of copies of the software program is a different version of a same software program, each of the plurality of copies of the software program are registered with a registry of the computer system such that at a same time each of the copies of the software program is separately identified in the registry of the computer system,

the default copy is a single copy of the software application that presents itself to a user or other software program as the only copy of the software program on the computer system at any given time, and

demoting the current default copy includes determining one or more features of the current default copy, and ensuring that each of the one or more features no longer exhibits a default interface on the system such that only one copy of the software program is operable at any given point in time and other copies, in the plurality of copies of the software program are hidden from users.

12. The system of claim 11 , wherein the global switcher is operable to receive user input selecting one of the detected plurality of copies of the software program to be a default copy through a user interface, and each local switcher is responsible for promoting and demoting a corresponding copy of the software program independent of the global switcher.

13. The system of claim 11 , wherein each of the plurality of copies of the software program represents a different version of the software program.