On a DELL computer after logging on you get a warning message:
The total hard drive capacity in your system has decreased. This typically does NOT indicate a hardware failure. Contact your Help Desk if you did not personally change your system’s hard-drive configuration or disable devices in System Setup.

In Addition following event is logged in Windows Application Logs
Source: OMCI
Type: Warning
Event ID: 2
Description: The total hard drive capacity in your system has decreased. This typically does NOT indicate a hardware failure.  Contact your Help Desk if you did not personally change your system’s hard-drive configuration or disable devices in System Setup.

In most cases this doesn’t indicate anything serious and often happens after you unplugged an external hard drive while your computer was off.

It’s not a standard Windows message. It is produced by an application called Dell OpenManage Client Instrumentation which normally runs in a background.
If you want can safely remove this application from Add / Remove Programs. It can be listed as OMCI.

DELL
Windows XP