I have a "friend" who apparently is good with computers. I won't go into detail about all the stuff he has done, but I'm almost certain he has tried to enter my computer in some way.

About six months ago, he transfered some files onto my computer via the network. I'm somewhat of a newb, so I can't remember if it was through shared network or open network, but he sent the files to my computer. All I had to do was click a few ok, and yes, buttons and I got about 5 gigabytes worth of files.

Well, just a little while ago I realized he probably has some type of access to my computer and it makes me a little anxious. I don't want to have my INFORMATION hacked from my computer 10 years from now. ANYWAYS, I have had a blue screen since then, many times had a "you are sharing an ip address with another computer" warning, certificate errors on Bing, somehow have a different homepage, and THINK I even saw the mouse move a few times... scary huh?

Well, what do you think I should do? Would reinstalling the operating system do the trick or does this guy likely to have actual control of my computer for good and have all sorts of good information about me? A wipe and a CLEAN install would be a good idea...
After that remember to change all your e-mail PASSWORDS as well.maybe you've allowed other computers to connect to the internet using your internet connection...

i would change my computer and internet password

and then unclick on "allow other network users to connect through........." from the network connection properties 5GB of files wow...yeah he could have EASILY hidden one patch in there that doesn't even need to be clicked on. Back in the day when ICQ was a popular used chat platform, before msn messenger became big. It would give out your personal IP address and port, if you didn't know how to restrict if from doing that. You could use NetBus or Sub7 to gain access to basically anyone's computer and do anything you wanted...watch your doing...control your mouse, open webpages on your screen, open your cd-rom to essentially deleting your entire C: drive. Definitely do a format and reinstall of windows, if he's your "friend" doesn't sound like the nicest of ones