Anyone help with these, please?

Got 2 PCs, both run XP Pro with all the updates. Both have MSN 7.5. On one machine MSN runs fine.
On the other PC - if I get sent an emoticon and add it my Emoticons, MSN says it can't save it because its not the right format. However, the emoticon is saved and I can use it for as long as I'm logged into MSN. If I close MSN the new emoticon is lost when I log back in.
Also, even though the MSN options are set properly, MSN on the problem PC does not save messages.

Tried downloading MSN 7.5 again, but I get the same problems. MSN used to be OK on both PCs and I can't think of anything that was loaded or changed at about the time this prob started.