You're referring to two different things...as if they are one.
a. Error messages are the messages that flash/popup while either booting or working in XP. Some are brief, some are persistent.
b. Event Viewer is a log of some error messages and other items which XP is designed to bring to a user's attention, in an effort to help troubleshoot actual and potential problems. Event viewer may not contain every error message ever generated, but it will contain some system errors that never generate error messages.
Microsoft Windows XP - Using Event Viewer - http://www.microsoft.com/resources/documen...r.mspx?mfr=true
One thing that prevents some errors from being reflected in EV is...the user. By default, there is a setting which tells the system to reboot when it crashes; in cases where this setting is the default (most systems), there will be no error entry in EV and the system will simply reboot.
That can be remedied, Disable Auto Reboot On System Crash - http://www.theeldergeek.com/auto_reboot_on_system_crash.htm
Once the setting is changed, there should be some data in Event Viewer. If you list the module and eventid here, someone will try to help. A verbatim copy of the EV entry would be even better.
From what I can see, that service/process relates to a backup service for Western Digital drives, see references at http://support.wdc.com/download/downloadxml.asp
Event ID 7000 just shows that XP has noted that a service failed to start for whatever reason.
And...there is no DOS in XP. So I wonder what you really did.
Anyway, if it were me...I would either patch/update the Retrospect software or remove it from my system. What's probably happening is that there is a reg entry for it to run and it's no longer on your system. The reg entry can be removed by using a utility like Autoruns.
You might also just take a look in Services on your system and see if it needs to be put on Auto start.
Those are my best guesses