Hello SoSnaz,
I would be concerned as well if my iPhone was not recognized by iTunes. I understand you have taken some steps to troubleshoot this issue, but I am not sure if they were the steps in the article below.
If you have not yet tried these steps, I recommend these next (you can skip the steps you have already taken):
iOS: Device not recognized in iTunes for Windows
http://support.apple.com/kb/TS1538
Thank you for using Apple Support Communities.
Best,
Sheila M.