Dear Red Dawn Thank you for taking the trouble to reply and for locating the update which seems after all to be genuine. Seeing that it was a critical BIOS update from an unidentified publisher, I was extremely suspicious to say the least. and in fact I thought it must contain a virus. If it weren't such a business getting in touch with Dell now that my warranty has expired, I would give them a piece of my mind. Thanks once again  
When I started my computer this morning (I am in the UK), I was greeted with an alert, allegedly from Dell Support Centre saying that my laptop needed a critical BIOS Update. When I went through the initial motions of downloading 1525_A16.exe, I found that it came from an unidentified publisher, so I did not run it. Has anyone else had this worrying alert? My laptop is a Dell Inspiron 1525 and I am running Vista.    
Critical BIOS Update alert allegedly from Dell Support Centre, but from an 
unidentified publisher.