Hacked, do I need a full reinstall?

Hi, I was waiting for my friend to finish up a code he made me. After a while he did and before I got on GMod he asked me to go on Teamviewer, so I did. After a few seconds I couldn’t move my mouse or do anything, he transferred a file and it restarted my computer. Now, whenever I open up my console it shows me the lemon party website.

Instantly I uninstalled TeamViewer, but I don’t know how to remove this hack; is there a quick way or do I have to completely reinstall the game?

By the way, the person’s name is Fishy Wishy.

Thank you

What? I don’t think that this is possible, pics pl0x?

I don’t have any images but there was a .rar file with nothing of any use in it and a file that seemed to extract other files or something. The file is gone so I can’t give you any information about that.

the lemon party screen, however, fills up my entire screen with it and at the top (it’s a derma menu) it has probably mock binary.

Also, if this helps, my computer automatically locked, it seemed that then he left teamviewer, he removed me from his friends and in a few seconds my computer restarted.

Edit: I reinstalled GMod by right clicking it in my library and clicking install, it’s not gone. Please help me.

another edit: I deleted steamapps/myusername/garrysmod and it’s not fixed.

Ooh look, another edit!: He also got into my server’s CP, is it possible that he made a script that checked that my steamID was playing and that it’s only making me run the derma?

I need to stop making edits…: This only happens on a server he managed to get access to.

[editline]31st December 2011[/editline]

I fixed it, I find the code he added.
Thanks anyway.

Just reinstall it.