Spyware and Administrator Status Question

Unfortunately I didn't read the Microsoft warning about the administrator being prone to more spyware/Trojan than a standard user, and now I believe a virus has changed the administrator account and I am no longer the administrator on my computer. Therefore, I cannot access my control panel to do routine task on my computer. When I try to access the control panel, internet options, etc. it says to contact the system administrator. Please give advise or something I can do to fix this problem. I hoped that Norton 360 would have detected the problem during routine scans but it didn't. Thanks.