As i posted in another post : if you have windows XP
There is only 1 way to fix a virus in System Volume Information
To get into system volume information :
Go into system restore, to the left, click "system restore settings" and turn system restore off. Press apply. This will purge all of system restore, restart the PC, and then you should hopefully be able to turn it back on
This is a protected folder for System Restrore, and that is the only was to delete it, You will lose all your checkpoints as it will delete them all. However as soon as you have restarted the PC you should be able to turn it on
As I said before, this is the only way to delete system volume info files, trying to delete them using other methods might cause damage.
If you have windows ME i suggest you follow this link :
http://support.microsoft.com/default.aspx?scid=kb;EN-US;q263455 It worked for me but had to unplug pc replug to get it started