System requirements for running Silverlight:

 

Compatible Operating Systems and Browsers

 

Operating System

Windows Internet Explorer 7

Internet Explorer 6

Firefox 1.5

Firefox 2

Safari

 

Windows Vista

Yes

-

Yes

Yes

-

 

Windows XP SP2

Yes

Yes

Yes

Yes

-

 

Windows 2000

-

Yes**

No

No

-

 

Windows Server 2003 (excluding IA-64)

Yes

Yes

Yes

Yes

-

 

Mac OS 10.4.8+ (PowerPC)

-

-

Yes*

Yes*

Yes*

 

Mac OS 10.4.8+ (Intel-based)

-

-

Yes

Yes

Yes

 

 

* Silverlight 1.0 Only ; ** Silverlight 2 Only

 

 

Minimal Requirements

 

Components

Requirement

 

Personal Computer running Windows

X86 or x64 500-megahertz (MHz) or higher processor with 128-megabytes (MB) of RAM

 

Mac OS 10.4.8+ (PowerPC)

PowerPC G4 800-MHz or higher processor with 128-MB of RAM

 

Mac OS 10.4.8+ (Intel-based)

Intel Core Duo 1.83-gigahertz (GHz) or higher processor with 128-MB of RAM

 

 

RECOMMENDED: Use Silverlight in the 32-bit Internet Explorer process on x64 systems. Most browser plug-ins (including Silverlight, Flash, Java and almost all ActiveX controls) only work in 32-bit browsers currently.

 

IE 6 supports Silverlight under Windows XP SP2, Windows 2000, and Windows 2003 Server only.  You should verify what OS the users are running to ensure that it's one of these supported ones.  Note that Silverlight is running fine in IE 6 under Windows XP SP3.