IE doesn't work, but FF does.

My ex-gf seems to have had a virus, and after a dose of BitDefender,
AVG, and Spybot S&D (just because she had it installed) I was making

Bitdefender found about 230 occurrences of 12 viruses, but they were
all in emails she received in 2003 and 2004 from an ISP she doesn't
use anymore, and she says she never opened any of them, and indeed she
has had no problems until last Friday. Yet the computer seemed to
work quite a bit better after they were deleted. ???

Then I ran AVG on Saturday evening and found a trojan (the name is at
her house) and a registry reference to it, and I quarantined or
deleted both of those.

At that point Firefox and IE still didn't work.

Then after I left she got a message in FF about proxies, and another
friend of hers toold her to go to
FF/Tools/Options/Advanced/Networrk/Connection Settings, and to uncheck
Use System Proxy Settings and use No Proxy instead. Then, voila, FF

But IE still doesn't work, and I don't know of any option for IE like
the FF option. Even more so, I would like to restore the System Proxy
Settings to what they must have been before all this started, so we
can go back to using the system proxy settings like FF intendd.

Googling for those three words finds almost nothing.

Any advice?

Thanks. Any help would be very appreciated by me and her too.