Have you tried using either the ClickLock or Mouse Keys features that are built into Windows? The combination should handle much of what your asking for.
The shortcut to the Windows Ease of Access Center is Win + U. Mouse Keys can be accessed directly from there and ClickLock is on the Activities tabe of the Mouse Properties dialog (which is accessable from the Ease of Access Center).
IIRC XP has both of these options available as well.
Thanks for that, I just gave it a try on Windows 7 and the movement is 10 pixels which is not accurate enough for what I am looking for and I could see no way of changing it.
I'll have to look and see if it can be changed in the registry, if I can find a key for it. (I just ran a registry search for 'Mouse' and turned up 790 keys but nothing for Click Lock.)Update
: Cancel the above I just discovered that if I use Ctrl + Arrow Key the movement is 1 pixel so you have given me a solution.
(I have just been experimenting and discovered that it does not work on everything. I have two desktop clocks, one digital, one analogue, it works on the first but while Click Lock works on the second the Arrow Keys do not, however I am sure that I will be able to do what I wanted to, so thanks again.)
After 7 years I am still finding things in XP I never knew about, I only started on Windows 7 six months ago so I have a way to go.
Incidently, Win + U has no effect on my computer, I tried it yesterday. I also tried clicking on the shortcut in All Programs\Accessories\Ease of Access for the Access Centre and that had no effect either although the rest of the shortcuts in that folder are all working. It might be because I removed it from the Control Panel, along with a lot of other things, as I have never had any use for it?