system keeps re-booting

Hi all, i am using Windows 2000 and i have just updated to the latest version of avast, released this weekend. However, since updating my pc re-boots itself. This will re-boot anything from straight away up to half hour at a time. Can anyone help???

I moved the thread into avast! cathegory - the topic doesn’t have much to do with “Viruses and worms”.
Please, check my questions there.