lsass/csrss driving me crazy :S

[F_A_F]

In the past week, csrss.exe and lsass.exe have been sending me slowly mad. They've recently decided to start increasing their memory load byte by byte, every second of every day of every week...etc. The only clue to their insolence is by opening task manager, selecting to view I/O Reads and I/O Read Bytes. Oh that, plus the fact that lsass accesses the hard drive once per second.....alll....the.....time. It's literally like having a 5kg PC shaped metronome on the desk, with the little HDD light going "flash, flash" and the drive going "grind, grind" once per second without fail. I don't even have to be logged in on either of the accounts. It never stops; playing a film, "grind, grind", playing a game, "grind, grind", browsing the web, "grind, grind".

Is there anything I can do to stop the damn processes constantly adding more bytes to themselves? Two day's worth of trawling the web has come up with several other folks who have the same problem, and NO further info from Micro$oft. Their bug reporting page doesn't work, plus as I'm OEM I can't even contact them....unless I pay $40 :(

Oh and by the way, I do know that lsass was involved in the Sasser virus a few years back, but I'm confident that this isn't virus related. I have a daily updated Norton AV running, plus I've scanned the system online a few times with Kaspersky etc....and nothing comes up as even slightly risky, let alone Sasser level of threat.

Any ideas?

[F_A_F]

Oh incidentally, I also have HDI installed (a basic HDD monitor) and it shows no activity at all on any of the drives, so heaven only knows why the "son et lumiere" show that is my HDD is happening....