Sorry to be late Nathy.
It sounds as if you are having a mouse driver problem.
Please give this a try.
Read this first.
Shutdown, restart, and sleep Vista from the keyboard
for tips on how to restart without a mouse.
Hit start| right click computer| properties| device manager.
Goto mouse and pointing devices and find your mouse.
Right click it and select uninstall.
When Windows restarts, it will load the standard Windows mouse driver, automatically.
I think this will solve your trouble.
From there you can get the newest version of your Lachesis driver and reinstall it.