dudio :
Open it up in Notepad/Wordpad and see what it is.
A cfg file on its own is harmless.
This is what was in notepad:
2047085504\+>5,dcg`-3,yskmxfaya>;>4;?+R,44>951=:+19,lmSsn-3,mn-1,1+S,p-04-,-,1,xSbmk12==<0/+S,hw2_=:8=,,,,lo1v-1-,+S,p-0,j+19,lhSbi`x>xon\lmap-0,hS29S82Pok2?8;6+26,`b-1,x-3,f-4,c-3,w2E+19.Gn
However, whenever this file reapears, a fake pc update window opens prompting me to update.