Have just done 4163 update together with the engine update to 4.1.50 i.e. SDAT - having real problems, lag on internet with lock ups etc., had to deactivate 'Internet Filter' which has improved matters considerably...it particularly hates Pprune I think because of all the banners!
Running W98, have Mc. Afee 5.21.1, never had probs before after doing an engine update...have complained to McAfee!