If your Trend Micro package shows in the Add/Remove window it should be easy enough to remove it. After removing I would run Ccleaner to remove all remaining fragments of the program.

But before removing it I would download your chosen anti virus and firewall program so that you can remove the internet cable while you do the removal and install process without fear. Be sure once the installs are completed and you re-connect to the net that you immediately look for updates, there will be some.

Thank you. I have to remove the DSL cable?

For safety sake, yes I would remove the DSL cable once I had downloaded my new programs. This way you can work freely with no fear of infection while doing your job.

Once installed you re-connect the cable and look for the updates to your new programs.

Thank you, didn't think of that as I had dial up until a few months ago. What is a good firewall and what else do I need?

I use and like zone alarm for firewall they have a free basic version.
For free AV you can consider Avast, Avira, AVG with out linkscanner (if you decide on AVG come back and ask and I can give you the link to that).
And for malware/spyware you definitely want superantispyware free which you do have to remember to update and run a full scan once a week. and definitely want spywareblaster which you have to update about once a week and hit the enable protection button, that will keep your browsers immunized and keep a lot of stuff from getting on in the first place.
here is a link that has the list of freeware you will need.
I caution people on the use of registry cleaners I personally do not use them or recommend them. That would be up to you.
SUPERAntiSpyware
Freeware

I downloaded AVG last night but didn't install. I got it from CNET I think. What is linkscanner? Sorry I am not very good with computers. I did download SpywareBlaster4.1 last night.

if you just download the version of AVG you will get linkscanner included, it has been the cause of some problems for some people causing slow downs and extra cpu usage so AVG put out a FAQ on how to install with out the linkscanner which is what many are doing and it seems to be much better.
to install AVG 8.0 Free Edition without the LinkScanner component,
It is always best when possible to download directly from the vendor site rather than some other site unless the vendor directs you to a mirror site for download. That way you know you are getting the latest versions provided by the vendor and less likely you are getting a compromised version.
Be sure you get the superantispyware free also it will clean any spyware from your pc when you updated it and scan with it weekly.
the spywareblaster all you do for it is hit update about once a week then hit the enable all protection button so the shield turns green that is it.