Hi, . Being an upgrade disc, your better off restoring Vista, and then, upgrading to win 7, it won't take long. When you do get back on the Internet, you can download Microsoft Security Essentials (MSE), it's free off the Microsoft web site.
Long story...I'll try to be brief.  I consider myself an intermediate computer geek.  Not able to find  what I think I need, so please be patient if this has already been asked.  Two year old Dell Inspiron 537 desktop, originally with Vista and the Windows 7 Upgrade Option.  Used Vista until the upgrade was available.  Upgraded and have used the upgrade for over a year.   Apparently, picked up a virus at some point within the last couple of weeks.  Not able to browse internet, but have internet connection.  Dell Support has been pretty useless, although, I like hearing the accents from those in India.  I have spoken hours with Dell Support and visited their forums, etc.  to trouble shoot.  Have Service Plan for hardware, etc, but no software service.  Dell wants a couple hundred to fix problem, if they can.  My IP Premium Service techs. tried to help over a six-and-a-half time period through remote access which, for some reason, worked well, at a considerably lower cost than Dell.   They finally gave in, and gave up.  They indicated that they had met their match and couldn't help.  Recommended reinstalling OS.  That's fine.  I can do that.  I need to know if I have to reinstall Vista to reinstall Windows 7 Upgrade, or can I reinstall the Upgrade only?  Had McAfee, but didn't help with virus.  Do not want to reinstall this again.   Will go with another anti-virus program if I can gain browsing/download capabilities once again. Was able to back-up/make copies of files from hard drive.  Not sure if infected files are included, but will scan before I attempt to use them.  It's been a nightmare week.  Appreciate any help that can be provided.  Never know what you have until it is gone...I know, I know, it's only a computer and internet, but do we miss it!  Currently using a Dell Netbook that I have limited access to.    Thanks.
Do I need to reinstall Vista, to reinstall Windows 7 Upgrade, or can I just 
reinstall Windows 7 upgrade?