Certifcate installation problem

[Guest]

Hi,
I have been trying to install a client certificate from a goverment website,
when i hae been issued the certifcate and install it, i get one of 2 error
messages:

Please verify that your csp supports any settings you have made and that
your input is valid

or

The private key corresponding with this certificate could not be found. The
certificate may already be installed.

After searching through net, all i can find on this is update win 2k, but i
have all service packs and hotfixes. I am logging onto a AD domain, win 2k IE
6.

I have admin permissions so don't think its a permissions problem.

Any ideas?

thanks

Steve