Two questions [HELP]

[Hazza]

1) Why doesn't Vista find my anti virus? I have to "monitor" it myself otherwise I get "Your computer may be harmed" - Its not my anti-virus software though because I've tried about three, it just doesn't seem to pick them up? (Also, Windows Defender never turns on automatically anymore?)

2) What is causing my DEP to close? Sometimes it says "IP Helper" but sometimes its like "Windows Host Service" and they are both being closed then my computer totally mucks up and goes to default settings most of the time.

Extra information:
I'm using a HP G60 laptop.
I've had it for a month now (this has been happening for about 2 weeks)
I have only a few programs install on here, such as, msn, paint.net, anti-virus, firefox + a few music editors.

Thanks to any person that gives me a good reply that may help and I may just +REP you if you sort this for me!

[scottish]

The name of antivirus software might help?

[Hazza]

McAfee at the moment, i've tried AVG + Kapersky?