How Do I Reconnect To My Wifi Network After Forgetting It

My co-workers can use the same network with no problem and with the same password even. I thought this will resolve on its own but it did not. I tried to reconnect again after a few days but still it won’t budge. I need help with this issue.

Other Info: My phone is NOT ROOTED and it’s Android Ice Cream Sandwich. I tried WiFi Fixer like everyone says but it doesn’t work. Please don’t advise me to do something about the adapter/router, since I have NO ACCESS or control over it since it’s at work, not in my house.

Also, even if I have access to it, it’s in a different language so no can do. I am considering of doing a hard reset or rooting it but I have too many files in my phone to back up, so I wonder if you guys have any suggestions first. Thanks.