3 Dell laptops freezing or not updating windows

I have 3 Dell laptops and have had problems with all of them. There are 2 Inspirons 1545s (less than 6 months old) and 1 1500 (2 years old). The 1500 has refused to configure some important Windows updates from it was new: in fact it took an age to configure the first 24 set of updates when I first connected to the internet and since then has tried to download and configure the same ones without success - it ends up removing them which takes at least 10 minutes before properly rebooting. It's my daughter's machine and I've advised her not to shut the pc down completely to avoid the windows updating routine but of course it makes her pc vulnerable.

The 1545s have been freezing and I had to reinstall Vista on one of them despite updating the Bios as directed and, after a week, it seems to be working normally. I've downloaded Microsoft Security Essentials in place of Kaspersky. The other 1545 (4 weeks old) started freezing yesterday and I'm waiting for advice from here and other support sites before trying any remedies. Some common denominiators to consider:

1. All have either Kaspersky 2009 (1500) or 2010 (1545) installed (from visiting the Kaspersky support site I note that a number of users have removed the application and replaced it with another brand due to freezing which makes me suspect that I'm have identical problems).

2. I've downloaded and installed MS office 2007 (a legally purchased copy) on to all 3 pcs; after reinstalling Vista on one of the 1545s I'm waiting before reinstalling Office again.

Can any experts out there advise if there's a common probelm with Kaspersky antivrus  and Dell systems? I'm thinking that this is probably the cause of my problems.

Many thanks guys!