Plug and play drive settings for system restore keep changing.

I have Windows XPpro, service pack 3, running IE7. The computer is

approximately 4 years old.

My plug & play drive settings in system restore keep getting changed. I

have system restore set not to monitor that drive because it hasn't got

anything on it except music and graphics. I'm not sure that it matters but

the drive is a Seagate Free Agent with 500 GB of storage.

From time to time I notice my system slowing down and when I check system

restore the setting is changed to "monitoring". Does anyone know how this

happens?

It's not the upgrade to service pack 3 that caused it because this used to

happen when I had service pack 2 as well.

One more question:

What is the best setting to use for system restore? I have the slider set

for the C drive to the maximum(12% of the disc space). Is that higher than

necessary?

My computer has 111GB Capacity without the plug & play and about 1/4 of it

is being used.

Thanks for looking.

Sandy