Yousuf Khan wrote:

I've often noticed that sometimes my boot hard disk goes crazy, disk
activity light flickers constantly, system becomes unresponsive, but
there's no particular process hogging the processor cores. I managed
to watch one such incident while Hard Disk Sentinel was present in
memory, and when I looked at the boot disk in the Performance tab, it
showed 100% activity, but data transfer was down near zero.
Obviously, I had to reboot the computer to get it back to normal.

I'm talking about Windows 7 Ultimate 64-bit in this case, but I've seen similar things happen under Windows XP Pro
32-bit in the past too.

That can be just the drive retrying on marginal sectors.

Post the Everest SMART report on that drive.

Another thing I noticed is that during this time, the System's own SVCHOST.EXE program is using up a lot of memory
too, over 300MB by itself!

Are you saying that it doesnt when that isnt happening with the drive ?

What could be happening here?