Alemod Torjan Problem

My Antivirus tells me that I have Trojan.Alemod virus in wininet.dll
file. I have Win XP Pro SP2. I tried all the tricks suggested in this
forum, but I'm unable to delete/rename or relocate wininet.dll. I get a

message that the file is in use by another program. I tried that in
both normal and safe mode and still got the same error when trying to
overwrite it. I also disabled system restore but still have the same
issue.
I have SpySweeper and I ran it with all available options, but it did
not find any issue, which is wrong.
My machine response time went down big time, it takes forever to open
things.

How can I tell which process is using wininet.dll?