Hi,
Take it step by step:-
Firstly, are your programs all working normally? e.g. MS Word, Adobe Reader, etc?
Secondly, this message saying that your AV is turned off: how professional-looking is it? Is the spelling/grammar of it correct? Are the logos a bit unclear?
My feeling is that this is something a bit dodgy-sounding i.e. a hacker or fraudster at work - have you visited any new or funny websites recently? Have you installed or downloaded something new.
If the answers to most of the above is "no", then I would give your computer a rebirth to start with i.e. do a system restore to a point b4 the problem start time: Go to Start > Programs > System > System Restore. It will take about 20 minutes, and will not affect your data, but I would back it up b4 doing this, just in case.
If this does not work i.e. sort your problem, then you might need to reinstall Windows, which is a bit more advanced and takes longer - you will need your Windows disk if your laptop came with one - otherwise you can do it from the operating system partition (a part of your hard disk that is reserved for Windows).
Keep me updated on your progress - I am happy to guide you.
If you are not very conversant with computers at all, another option is to take your PC to the PC helpdesk at your uni - usually situated in the main library - they are trained to handle most common issues.
M (MSc CS)