Windows Task Manager wont open?

this is abit weird... one day i start my computer n i try to open Windows Task Manager but a message pops up sayin "Task Manager has been disabled by your administrator.." the thing is , I AM THE ADMIN OF THIS COMPUTER .. i was troubleshooting myself and iv come up with these solutions.

Since my father is connected to the network and doesnt understand english well -_-' maybe he tampord wit somthin and doesnt remeber

Maybe a hackker? lol

somthin to do with the second user account on this computer..

thats pretty much wat i came up with..so if someone has any suggestions on what to do then plz reply

P.S YES I WAS UNBANNED

 

system restore ?? but iv got important files added daily . i cant do that

 

heheh um.. this may sound a bit dumb of me ... but my last restore point was 1 min ago... cuase system restore was never actualy on.. lol ,shuld i just reinstall windows?

 

ok im gonna reinstall windows intself not the data just windows .. thanks for ur helps anyways