As support for Windows XP officially ended on April 8th, you kind of need to rely on yourself now to ensure that your machines is still secure. Like many people, I've got an old computer that still gets some occassional use - and therefore needs as much security as it can get. But oftentimes, safety doesn't go hand in hand with compatibility.
After looking around on the Internet, I decided to enable DEP (Data Execution Protection), an anti-exploit mechanism, for all programs. This method has been encouraged by sites such as Tom's Hardware and Pc Mag, and after weighting the pros and cons decided to enable the feature on my computer. Simply right-click on My Computer, select Properties, Advanced, Performance, and Data Execution Prevention.The picture below shows it turned off - click the appropiate box to enable it for all programs and services.