The first four lines of this code will give you reliable YY DD MM YYYY HH Min Sec variables in XP Pro and higher.
Your description is very vague but this has lines below which delete a file if it exists or not, so you can create new data in the same filename.
@echo off
for /f "tokens=2 delims==" %%a in ('wmic OS Get localdatetime /value') do set "dt=%%a"
set "YY=%dt:~2,2%" & set "YYYY=%dt:~0,4%" & set "MM=%dt:~4,2%" & set "DD=%dt:~6,2%"
set "HH=%dt:~8,2%" & set "Min=%dt:~10,2%" & set "Sec=%dt:~12,2%"
set "datestamp=%YYYY%%MM%%DD%" & set "timestamp=%HH%%Min%%Sec%"
set "fullstamp=%YYYY%-%MM%-%DD%_%HH%-%Min%-%Sec%"
echo datestamp: "%datestamp%"
echo timestamp: "%timestamp%"
echo fullstamp: "%fullstamp%"
del "c:\path\to\folder\abc_%datestamp%.xml" 2>nul
echo do something with "c:\path\to\folder\abc_%datestamp%.xml"
pause