I had 4.10.5 installed and it was working fine last night, but when i got home from work today 4.8.1 was installed and no one has installed anything today.

Should i question what happened, or should i just re-install the latest version?

Either your brother or friend is playing tricks on you or you're logged into a different account which has a different version installed. Either that or the phantom installer has ... oh better go easy here .... will o'the wisp! Reminds my of the ghost busters for some reason ... when one of them got greased!~ lol

Thanks, i think i'll limit some of the user accounts so they can't install programs without my password, that'll sort out any future install problems.