Thank you. Now what I did have last night was that it shut down windows and then prompted to start windows after which it went through a chkdsk procedure. It mumbled something about needing to address C: and NFTS and Vista and one of the discs needing to be checked for consistency. It ran the chkdsk utility indicating that it was recovering lost and orphaned files and that it was correcting errors. Seems to run normally again now. Should I worry? Thanks.