After a visit to my Linkedin account it seems like every one in my Gmail address book got an invite!
People are very annoyed!
Is this a virus?
Are you trying to say that everyone that you have added as a friend got an Email that you did not send them? Is you’re system acting up in a funny way are you getting any redirects? Such as going to places that you have not typed in or are searching for?
It could just be Linkedin sending out invites as you may have unknowingly clicked upon a link on your homepage. I don’t use Linkedin that much but i know Facebook has a link, which pops up from time to time asking you to invite all your email contacts.
No…it sounds as if some server went nuts. Check your Linkedin account settings.
I would suggest you scan using MalwareBytes and Super Anti-Spyware. Both are free but you will need to “update” each before scanning. Another good download is CCleaner. The links are below.
http://filehippo.com/download_malwarebytes_anti_malware/
http://filehippo.com/download_superantispyware/
http://filehippo.com/download_ccleaner/
Hope these help. 
There were recent security breach with Linkedin. I would change your passwords with both Linkedin and Gmail and make them both different and stronger, and delete your contacts in Gmail for now. You can also notify Gmail of what is happening as well.
In addition, follow the previous suggestions on doing scans with MBAM (Malwarebytes), Avast Quick scan and boot-time scan. You can cut and paste your MBAM scan here. Remember you need to update MBAM prior to scanning and quarantine any infection that is found.
As a safety precaution, you should us add-on’s in your browser (see my Signature as an example) and clean out your Internet history after browsing…that is why we suggested CCleaner after you surf. There is a Slim version of CCleaner available without toolbars at http://www.piriform.com/ccleaner/builds – 4th option down.
Let us know if you have any additional questions. Thank you.