Harper - My Own Expense? It's not even my computer.
You're reading the post, so my humor is at your expense.
I am trying to help out a freind with this. And if you're not going to help out, then bugger off and final another thread to paTROLL
You weren't doing much either. His system specs don't tell us much in this problem.
If you've already swapped keyboards and mice, and still found the same problems, you can ditch those.
This sounds really like a driver issue. Either mobo, or mouse/keyboard. Something's getting hung-up on the system.
When his mouse kicks out and he starts endlessly walking off in one direction, does the game lag then? Or is the lag unrelated to any actions of the mouse/keyboard?
Lastly, what happened when you tried a USB mouse and keyboard? There may be something wrong with the ports themselves. If you transport the case a lot, or are constantly yanking the mouse/keyboard cables out all the time, this could very well be your problem.
On a hardware note, it is also possible that something is flaking out on the mobo. Check his RAM, check his processor temps.
Also, what OS (and what update) is he running?
Oh, and what game? I know there's a couple games on the market that have mouse/keyboard issues and you need to use a patch.