The IT Stuff

Server-specific Requirements:

Windows Server 2003 x64 and have SP1 installed.
.NET 2.0 Framework and MMC 3.0
Any Intel Xeon or Pentium 4 64-bit processor
Any AMD Opteron or Athalon 64-bit processor
1GB of RAM plus 7MB per mailbox
1.2 GB of available disk space on the drive on which you install Exchange
200 MB of available disk space on the system drive
DVD-ROM [...]

Exchange Server 2007 includes built-in protection with features like Edge Transport, Hosted Filtering Integration, and anti-spam filtering and extensibility for antivirus protection
MS Exchange 2007’s built-in message indexing capabilities make locating messages quick and easy.
Always-synced “push” mail on any Windows mobile device.  With new Windows Mobile 6.0 devices, your users can search their entire mailbox from [...]

If the mails are not deliver then With the help of NDR (Non-Delivery Report) the server  tells  the  client about the status.
NDR List of Codes and their meanings to reslove the problem
Explanation of Non-Delivery Report error codes for Exchange Server
4.2.2
The recipient has exceeded their mailbox limit.  It could also be that the delivery directory on [...]

Windows Server 2003 includes 11 roles administrators can assign to servers by using the Manage Your Server Wizard.
Terminal Server:
Provides a single point of installation that gives multiple users access to any Windows Server 2003. Users can run programs, save files, and use network resources from a remote location as if these resources are installed on [...]

Perform Analyze before defragmenting a volume

Analyze volumes before defragmenting them.
It tells you the percentage of fragmented files and folders on the volume
Recommends whether to defragment the volume or not .

Analyze after adding large numbers of files

It is best practice  to analyze Volumes  because it becomes  excessively fragmented when users add a large number [...]