1 - Internet Service Provider (BT, NTL, AOL etc.)
2 - Operating System (i.e. Windows ME, Windows98 SE, Windows 2000 etc). If you are not sure, follow these steps (for Windows):
a. Choose Start/Run
b. Type winver
3 - Use Help/About and write down the exact text that describe the browser version. For IE on Windows, that can be like this:
Browser version: 6.0.3790.0
Update versions: Q2355;SP1;