Ive spent the last three days doing exactly the same, installing eset - nod32 and removing sophos!
not the easiest job in the world but im about there....... the eset manual aint that great!
just to say ive got the script working perfectly, its worth taking out the first and last "pause" the script will then run silently on log off via group policy! it does extend log of times by about a minute but with a network of 1250 machines its by far the best option!
s