Disk Queue Length always high, even with no requests...

I was working on my server this weekend trying to figure out why I'm
having the problems some of my users are reporting.
After I got done running a dbcc dbreindex, I noticed my average disk
queue length (even over several hours) was a solid 4.337. The perfmon
would show disk IO in large spikes (into the 400s) several times per
polling intraval (1:40 according to perfmon).
This is a bit odd to me, as the system does nothing but serve the SQL
database. Nobody but myself was attached to it.
So, I grabbed process explorer from sysinternals. I was watching the
disk i/o in that, and according to it, the program causing the disk i/o
spikes is csrss.exe (required by windows).
This machine is not connected to the outside world, just to our lan.
However I guess it's possible a virus made it's way to the machine.
But I'm not entirely sure that's the problem.
At any rate. What can I do to get rid of that high of a disk i/o? I've
monitored it before and never seen a steady 4.337 (steady, unwavering)
I/O reading.. especially with nobody on, let alone 30 users.Ahh, system specs just in case
2GB ECC RAM (Tossing in 2 more GB for the sake of it).
RAID1: 160GB Mirror Array
AMD X2 4400+ Toledo Core.
All this machine does is serve up a 7GB MSSQL db to about 17 machines.
However, most of these users are not active throughout the day.
I realize the mirror array is not the best way to do it. But we are
more concerned with data safety than speed. (for the most part).
I'm just trying to narrow down why my average disk queue length is
currently in the 4's with nobody on.|||Alright,
We can nix this topic. I came in this morning and the averages were
under 1. It must have been in a grow op or something when it was in
the 4's constantly.