it's a common problem
Hey Stevo,
This problem happens from time to time, and it can be caused by many things, so the exact problem is hard to diagnose. A quick search of the Internet reveals that Java is often the culprit, so a first step would be to visit the Java site and update to the latest version and see if that helps.
http://www.java.com/en/download/index.jsp
Another thing you can do is try to recall if you installed any new software at around the time the problem started. Openoffice or HP software can sometimes be to blame, so you can try uninstalling those if you have them and see if the problem fixes itself.
A more advanced step to try would be to check to see if you have any tasks scheduled. In Vista, this can be found by typing "Task Scheduler" into the search bar in the start menu (click the windows button in the corner, the search bar is the white box at the bottom with the magnifying glass). In Task Scheduler, you will see a list of tasks that have run, and are waiting to run. If you see any tasks that you know for sure don't need to run, then you can try stopping them, but if you don't know what you are doing, its probably best to just leave these alone so you don't do more harm than good.
Sometimes the problem will just rectify itself, so it might just be easier to ignore the problem for a while and see if it just goes away. If it is really an issue, you can take some a more drastic step like doing a system restore, but this would probably be a bigger headache than a small error message popping up from time to time.
Hope this helps. Cheers =D