guys thanks for the advice i started following gerbils advice but not had much luck as the system appears to be locked down by whatever virus etc is on it. When i try to run combofix I get the error Windows cannot find regedit.. Ive attached screenshots for reference.

I tried to run regedit manually from run but recieve the error - another program is using this file.

I managed to run Ccleaner which appeared to clear out a lot of things. and finally i tried to install AVG but it wouldn't let me do so, again Ive attached the error.. i think the system is screwed, but imj happy/willing to try any further advice if anyone can give it?