Trojan Horses - Unable to Remove

Hello,

Norton has detected two viruses on my system:

1) backdoor trojan (didn't specify which exactly)
2) bllodhound.exploit.6

It hasn't removed them and when I tried follozing the instructions for
manual removal, the registry parameters indictaed in the insturction
didn't exist in my registry. In the case of bloodhound, the
instruction indicated it was an outlook express trojan, and I don't
even use outlook...

Any idea how to remove them anyway?

The main problems I am experiencing at the moment are slow startup,
machine hanging, inability to download large files (says there's not
enough disk space although there's plenty).

I understand reformatting the computer is not advisable. How about
reinstalling Windows ME?

I am sort of at the end of my rope having tried any anti virus out
there. Any ideas???

Thanks,
Michal