Hello,
Is this issue occurring on all client machines or only on 1 specific XP client machine?
Could you specifically state - what issue are you facing, so that we could assist you better.
Any Particular Reason, you want to uninstall SEP 12.1 from your machine?
Since you are running SEP 12.1 on your XP machine, you would require Symantec CleanWipe version 12.1.
This utility is available with Symantec Technical Support.
How to get the CleanWipe tool (Endpoint Removal)
and
Check this Article on:
Methods for uninstalling Symantec Endpoint Protection
Secondly, incase your issue requires urgent attention than I would suggest you to create a Case with Technical Support.
Either create a Case online by following the steps provided in the Article below:
How to create a new case in MySymantec (MySupport)
http://www.symantec.com/docs/TECH58873
OR
Call Technical Support -
Regional Support Telephone Numbers:
United States: https://support.broadcom.com (407-357-7600 from outside the United States)
Australia: 1300 365510 (+61 2 8220 7111 from outside Australia)
United Kingdom: +44 (0) 870 606 6000
Additional contact numbers: http://www.symantec.com/business/support/contact_techsupp_static.jsp
Hope that helps!!