Logging On Error

"Windows cannot load the users profile but has logged you
on with the default profile
for the system.

DETAIL - Not enough storage is available to process this
command."

I get this every single time I log on. I have PLENTY of
hard drive space left. In fact, the computer is only
about a month old. I'm the only user account on the damn
thing (besides Administrator).

How do I get rid of this?? When I first got my computer
logging in was extremely fast, then it got extremely
slow, and is still extremely slow, unless that error
message pops up (which is 99% of the time)...and then
it's lightning fast like when I first got the computer.

Any help??

Logging On Error