Hi,
I'd definitely suggest running the following tests first
Shut down the notebook.
Tap away at the esc key as you start the notebook to enter the Start-up Menu. Select the Bios option ( f10 ) and under the Advanced or Diagnostic tab you should find the facility to run tests on both the Hard Drive and Memory. Post back with the details of any error messages, including any codes.
Regards,
DP-K