You can use the following compatibility matrix for comparing Oracle and Windows platforms.
| 
 Oracle Version 
 | 
 Supported OS 
 | 
| 
 Oracle 9i 
 | 
- Windows Server 2003 (x86)
 
- Windows Server 2003 R2 (x86)
 
 
 | 
| 
 Oracle 10g r1 
 | 
- Windows Server 2003 (x86)
 
- Windows Server 2003 R2 (x86)
 
 
 | 
| 
 Oracle 10g r2 
 | 
- Windows Server 2003 (x64)
 
- Windows Server 2003 R2 (x64)
 
 
 | 
| 
 Oracle 10g r2 
 | 
- Windows Server 2003 (x86)
 
- Windows Server 2003 R2 (x86)
 
- Window Server 2008 (x86)
 
 
 | 
| 
 Oracle 11g R1 
 | 
- Windows Server 2003 (x86)
 
- Windows Server 2003 R2 (x86)
 
- Windows Server 2008 (x86)
 
 
 | 
| 
 Oracle 11g R1 
 | 
- Windows Server 2003 (x64)
 
- Windows Server 2003 R2 (x64)
 
- Windows Server 2008 (x64)
 
 
 | 
| 
 Oracle 11g R2 
 | 
- Windows Server 2003 (x86)
 
- Windows Server 2003 R2 (x86)
 
- Windows Server 2008 (x86)
 
- Windows Server 2008 R2(x86)
 
 
 | 
| 
 Oracle 11g R2 
 | 
- Windows Server 2003 (x64)
 
- Windows Server 2003 R2 (x64)
 
- Windows Server 2008 (x64)
 
- Windows Server 2008 R2
 
 
 |