Slow computer, Malware?

I have used Malwarebytes (about once a week) for about a year, then didn't use it for about a month. When I recently tried to launch it, the hourglass would just blink once, but not launch the program. I uninstalled it, then re-installed it, ...same results. The only "unusual" thing that I can think of that might be a factor: We received some emails from our niece which simply had a link on it. I opened the link, and it was some kind of pharmaceutical ad. I asked our niece about it, she said she didn't send it; ..bottom line, we concluded that someone had hijacked her email address. I advised her to delete her screen name (aol). I'm embarrassed to say I don't have an anti-virus program; I do have and use AdvancedSystemCare, which has not indicated any problems.
I have Windows XP (Gateway desktop).
Thanks in advance for any help you can give me.

By posting just a description of your problems it is likely that your topic will be passed by and you will not receive the help you're looking for.

We need to know what's running on your computer so that we can give you appropriate instructions.

May I draw your attention to THIS topic, which you should have read, and which tells you what we need you to post so that we can help you.

This thread will now be closed.

If you still need help, please start a new thread with:-

• A HijackThis log.
• An Uninstall list.
• Details of the problems you're experiencing.

If for any reason you can't run HijackThis, please let us know in your post.