I have 3 PCs hardwired thru a DG824M plus one wireless laptop. Something has changed since I updated by Norton AV etc. My main PC will not recognise the netwrok nor the other PC see mine. Other PCs see each other work fine. All 3 have access to internet. Checked work group name. Done spyware and AV run, seem ok. Checked Windows firewall off. 824 recognises all PCs are connected. Any ideas?