Most University PCs are managed by IT Services. On the majority of these computers, you will not have administration rights - that is you are not able to install software on your computer. If you have administration rights (or are unsure whether you have administration rights or not), seek advice from the IT Services Service Desk immediately.
If you think that your computer has been compromised, there are several things that you must do - refer to IS advice on what to do in case of compromise.