Do I need tasks "services", "lsass" and "svchost" to keep running??

yes you need all three of them.
you can go to administrator tools and run performance
and add counters for Processor, Memory and Hard Disk and figure out which
one is bottle neck.
most probably processor or memory...and you can upgrade both of them.

"Pankaj Dhingra" <pankaj@dhingrafamily.com> wrote in message
news:373901c34036$a2b776d0$a601280a@phx.gbl...

> My PC continuously access the hard drive .... the
> intermittent noise drives me crazy. Basically the three
> tasks do all of these accesses - "services", "lsass"
> and "svchost". Does any one know what these tasks do and
> if I need these to keep running on the system.
>
> Thanks for any clues that you might be able to provide.
> Best regards.