Is Lienvdk.exe a virus?

[randr]

Yesterday I received two suspicious emails from my ISP server. They each had a .zip file attached and I am afraid I may have executed one by saving it to a file to look at with winzip.
Then I did something dummer. I left for the day and forgot to turn my system off. Returning late last night I found my computer locked up and when I hit the CTL/ALT/Delete buttons I noticed a file , Lienvdk.exe, was operating and could not be closed out. I rebooted and my dial-up executed and froze the system again. Other obscure issues popped up as well.
I call my ISP system support was told to unplug tele connection immediately, which I did, and then to install a newer virus protection system asap.
I decided to investigate further and found the Lienvdk.exe file buried in the WIN\SYS. It was dated as of yesterday and was installed while I was gone. So I deleted it. Rebooted and all seemed well except that Internet Explorer attempted to open up a media site that was not supported. Odd, since I never use IE as I am partial to Netscape.
I went out and downloaded a new version of my Fix-it program, which took me almost all night. Installing the new version, Fix-it5, a problem message popped up, Problem 1721, but it continued to successfully install after hitting the OK button.
I ran virus scan and all was well.
This morning I opened up and got the same IE window opening. This occurs simultaneously with Netscape opening. My mouse froze up and I could not get anything to work. Hitting Ctrl/Alt/Delete again to see what was running I discovered another odd file. Usdo.exe had installed when I went on line and when I closed it the problems went away.
My question is what is Lienvdk.exe and Usdo.exe and does anyone have any experience as to what to do.
Thanks for any help at all.

[welshTerrier2]

1. it's an email worm ...

read this: http://securityresponse.symantec.com/avcenter/venc/data/[e-mail]

[randr]

2. Thanks welshTerrier2

All appears well----Whew!