it'll reinstall the nessesary bits over the top of your original os and you won't lose nowt

dont press D!!!!!

for a more indepth procedure try googling "how to use the repair function in xp"
and follow the guides there.

So it's supposed to be as easy as choosing R?

I've got the same problem and I've been using a Microsoft fix which is very involved and uses Recovery Console with command line entries.

Can you please elaborate or revisit this topic?