Hi there Steve_Birm, and welcome!
I'm glad you were able to resolve this problem. Looking at the info available for System Fix, it's probably the case that you became infected when you visited a malicious or compromised web site that exploited a vulnerability in one of your browser's plugins. Plugins are third-party programs that give your web browser extra functionality like Adobe Flash player or Java.
One of the best ways of protecting yourself from this sort of attack is to regularly make sure that all your plugins are up-to-date. For most browsers you can simply visit this page
to see the status of all your installed plugins. If one or more of your plugins are listed as vulnerable you should update them immediately. Make it a habit of coming back to that page every week or so, and in every browser you use.
Up-to-date plugins (and programs, and operating system) combined with a decent real-time anti-virus program will protect you from the vast majority of nasties lurking out there on the internet.