Following are the system requirements to install SQL Server Workgroup Edition:

Processor:
600-megahertz (MHz) Pentium III-compatible or faster processor; 1-gigahertz (GHz) or faster processor recommended

Operating System:
Microsoft Windows 2000 Server with Service Pack (SP) 4 or later.
Windows 2000 Professional Edition with SP 4 or later.
Windows XP with Service Pack 2 or later.
Windows Server 2003 Standard Edition, Enterprise Edition, Datacenter Edition with Service Pack 1 or later.
Windows Small Business Server 2003 with SP 1 or later.

Memory:
512 megabytes (M of RAM or more.
1 gigabyte (G or more recommended

Hard Disk:
Approximately 350 MB of available hard-disk space for the recommended installation.

Approximately 425 MB of additional available hard-disk space for SQL Server Books Online, SQL Server Mobile Books Online, and sample databases.

Drive:
CD-ROM or DVD-ROM drive

Display:
Super VGA (1,024x768) or higher-resolution video adapter and monitor

Other Devices:
Microsoft Mouse or compatible pointing device

Other Requirements
Microsoft Internet Explorer 6.0 SP1 or later

For Reporting Services, you need Microsoft Internet Information Services (IIS) 5.0 or later, and ASP.NET 2.0 or later

Thanks!