Microsoft Morro is lightweight, has a simple and intuitive user interface and gives basic protection just like any other anti-malware suites do. If you are going to go for any anti-malware suite, this should be the one. Morro has been warmly welcomed and has received many excellent reviews from trusted sites.
It totally rocks and you can even run scans while doing your work without caring as long as you have a computer with over about 1GB RAM. Unless you are looking for full feature security suites, I seriously advice you to go for this. Because it uses the same engines as Microsoft Forefront Client Security, it can definitely be trusted and relied upon.
By the way, I have sent you the Link Via PM. Cheers