Sounds like either a driver issue or an OS corruption.
Try pressing F8 or Shift+F8 repeatedly during boot up until the advanced boot menu appears and see if you are able to enter Safe Mode. Once in Safe Mode you can go to Control Panel - Device Manager and see if any devices are remarked with a question mark or Exclamation point. If so, you can try right clicking on them and selecting update driver and then update automatically. If that won't work you can double click the item to enter it's properties and try doing a driver rollback. A third option is to manually download the appropriate drivers from the manufacturers product page for your model of notebook and install them.
If there are no driver issues it may be a file system...