Computer control slipping away

 I'm never sure if I am in the place to be in too list the slow and somewhat painful take over of my PC -- Iam the only person on (Network) home PC -- but no matter what program I run to find it I have a ghost in my machine -- a list of thing from many thing -- refuses to make changes - tells me I don't Admin rights -- find program stashes under programs I do not use (I find

list or copies of list different programs) -- Have processes running that I have no ideal why they are there  and the things they run or will not run -- I have found listings of Shared access by a list of different NT window personnel -- in secuty listing  I find

trusted installer, trusted creator, administrators, and so on -- I have been refused access to my different drives (this may seem funny but there will be a little icon of to people on the things the ghost takes over -- when I get try making any changes in my security setting or do anything to find and get rid of the ghost my PC will start to run badly as if I have triggered some hidden program -- I'll start getting popups that a program is no longer there or some problem in system 32 does not know or can open programs -- to be truefull i have even reformatted and reloaded window 7 (and all the other programs that where lost -- I have changed settings for my router (this is when my PC starts acting strange - but if I change things back suddenly my computer will start working OK) changes made to router should not change the operation of my PC -- I know it seem like I am babbling -- but these thing happen -- (I keep all my programs up to date -- Norton , windows 7 and office 2003 -- any help