Cannot upload

Forced into putting XP on computer a few days ago, I have encountered loads
of problems. The most annoying one currently is the inability to upload to
group on Yahoo. System locks up completely and has to be unplugged to shut
down. All this stemmed from upgrading by adding second Hard Drive which
wiped out Windows ME. (Thank you, CompUSA). Not sure if the second HD is the
problem although it was installed as a slave.
Any help will be greatly appreciated as I am going mad and started to look
around for a hammer. LOL.