Hi,
The service ran on Window NT 3.1 but I am sure you can still write one for whatever his OS is.
If its windows another prank I have done is use 'hooks' to intercept keystrokes and randomly replace some keys with a double strike and others with no strike the last sentence may have been something like -
f its windowss ....
But only do it for a minute or so and then resume normal behavior for an hour or so, this one can gone on for years - 'I am sure its the ********* computer, this is the second keyboard I have used in six months' etc etc.
Duane B