A couple of nights ago whilst on the internet, a message
flashed up on screen stating "d drive not accessible".
I later found my D drive is locked out,I cannot access it
at all. When I checked the properties for both C and D
drives via my computer,the C drive details popped up
within a couple of seconds, the D drive details took
almost a full minute and then showed "free space =0, used
space =0, this is a 40Gb drive with 22Gb of vital info on
it,also the drive title had been erased.
When I asked the system to scan the drive for errors, I
got the message :- "Scandisk cannot check this drive now
because it is not formatted properly, or a program such as
a disk utility has locked it".

I have Ontrack disk manager on C and running this showed
that the drive is ok and that all the details of drive
size, and amount used were correct.

The Bios info on the drive is correct,The driver details
in System info are ok. I have run virus checkers,spyware
checkers and have even reformatted the C drive and
reloaded everything and am no further forwards and have
now run out of ideas.
Any pointers would be most useful