Then make it so simple, I don't know how they can afford to pay thier staff.
http://www.microsoft.com/security_essentials/

Here is a link that might be useful: Free - Microsoft Security Essentials

the free ones like AVAST, AVIRA etc also have paid versions they make their money from those and are wonderful in that they also offer a free version to help those who can not afford to pay, the free versions have a bit less on them than the paid versions of course. It benefits everyone when each person can have good updated programs on their pc which is why many of the companies do offer a free version.

In pay versions Kaspersky is an excellent choice, it is likely the one I would choose if I used a pay version it or Nod 32.

I personally use AVAST free on my windows machines and feel it is an excellent product. The main thing to remember is layered security so along with your fully updated Antivirus you also need good antimalware programs like malwarebytes and superantispyware which are also free which should be updated and run full scans once a week or so. In addition having spywareblaster is another layer that protects you while online and requires no scans just update it weekly and hit the enable all protection button so the shield is green. And of course a firewall, if you have a properly configured router you have a hardware firewall there protecting you but you should have a software one also, vista and windows 7 have a decent one built in.
SpywareBlaster
SUPERAntiSpyware Free

I think you have malwarebytes already?

you will of course have to get Trend Micro fully removed from the pc before changing to any other antivirus program.

as important these days is to make sure everything is kept updated and patched using Secunia tool makes that easy
Secunia Online Software Inspector (OSI)

My Avast often updates twice a day on my XP machine. I use WSE on my Win 7 laptop. I also have the other anti-malware programs that Raven suggests.

I am completely satisfied with the protection I have.

How do I uninstall Trend Micro Internet Security Pro and Trend Micro Internet Security 2008 from my computer?

Here is a link that might be useful: Trend-Micro

Here's Trend Micro's support page for uninstalling....

Here is a link that might be useful: http://esupport.trendmicro.com/consumer/answerguide.aspx?ag=80

New version of MSE released today. Look for the upgrade through your utility, or it can be obtained via this portal.

On the middle of the page is all the defined versions for selection.

DA

Here is a link that might be useful: MSE

All too often users are not fully informed, inexperienced, or sheep-like in how they blindly follow others in utilizing applications. May I suggest you go to the link below and register. On the toolbar is VB100. Clicking on it will provide a drop down menu. Besides reviewing anything you feel is pertinent, I ask you review the Archive and Recent Test Summary entries.

I think this information will help you make an informed decision.

Here is a link that might be useful: Virus Bulletin