no softwares can be installed.
Sandy: If you have a lan then just use that to a wifi router, but…. ask yourself why your employer hasnt already done this for you, adding wifi opens up more security concerns and is probably not allowed, if you add your own device to their network are you in breach of their security policy and subject to disiplinary action, adding wifi without correct setup is like adding a back door to the system. If you have a need for the access contact your IT helpdesk and ask about installing it officially. Note as well if you are in the finance or connected business adding your own wifi without authorisation could be classed as a breach of local computer access laws
Look up USB WiFi Dongle on Amazon or Google.
You can add a wireless network card to your office PC and then set it up to share the network through that.