I realize that "high" is a relative and an opinion term as opposed to facts.
So let me be more factorial.

I have had at least a 5 ~ 10 puters in the shop over the last 2 years
because the client connected and/or disconnected a PS/2 mouse with power on
and it fried the mobo. The client had done this action less than 10 times
total before it fried the mobo. I have never had a fried mobo in the shop
for connecting and/or disconnecting a serial and/or LPT port. I have had
about the same number of fried mobos in the shop from clients that did not
have a surge protector on the phone line going into the modem. I have never
had a fried mobo the shop that the client did not surge protect the AC line.

From these facts, I would suggest that connecting/disconnecting a PS/2 mouse
with power on and not surge protecting your modem phone line is a high risk.
Not protecting the AC line for surges (not applicable to 7/24 systems
without a UPS) or connecting/disconnecting a serial or LPT port as a low
risk.

I would not call you lucky but you have been going against the odds. Or
another way of saying it would be there are two kinds of people who
connect/disconnect PS/2 mice with power on...those that have fried a mobo
and those that will. <G>

Daniel Wysocki
Twin*.*Star Computers
770-498-2582 / 800-816-0663
[log in to unmask]
Fast - Reliable - Wallet Friendly

-----Original Message-----
From: Herbert Graf <[log in to unmask]>
>
>        While there is very likely a risk, I doubt very much it is "high".
I have
>unplugged MANY keyboards and mice without ill effect, maybe I was just
>lucky, but... TTYL
>
>                         PCBUILD's List Owner's:
>                      Bob Wright<[log in to unmask]>
>                       Drew Dunn<[log in to unmask]>

                         PCBUILD's List Owner's:
                      Bob Wright<[log in to unmask]>
                       Drew Dunn<[log in to unmask]>