Internet Explorer stopped working

Hello,

Last year my Windows Vista machine no longer let IE open. Can not connect to INternet; however the Internet connection is fine. Everything else works. I restored to a prior date for temporary relief, but with each new download, it stopped working. Virus? I tried to do a restore later in time, but the restore points are all after the initial "stop working" date and I can no longer get it to work. I gave up and bought a nice MacBook Pro, but would like to get my old Windows machine back for use as an extra pc. Any ideas??

Thank you