Greetz
I am in the business of computers and a large part of that is repairing them. If I understand you correctly you used an installer for a game mod, which apparently did not complete, you deleted something (unclear as to whether that was just the binary you downloaded) and shortly after your problems began.
Certainly you can overcome this problem by re-installation but you will lose all your saved games and other important settings and data if it was not backed up. I'm going to assume that like most people you'd rather not lose all that, so put re-installation on the back burner until you try a few things.
Firstly, your game mod installer, if it ran at all, very likely wrote something to the system, and most importantly entries in The Registry. If you simply deleted the original file these will remain and will cause your system to try to access files that no longer exist. Computers aren't smart, they're just fast and it has no way of knowing you deleted anything... only that it can't find it (them) and continues to poll to try, often ad infinitum.
Assuming you are or would like to be in charge of your computer, consider the following:
So the first thing to do (after backing up - more on that shortly) is to launch Regedit and use the "Find" function (subsequent same search just use F3) for the name of the file and/or where you directed it to be installed. Example - let's say the mods name was "foo.exe" and when it asked you where you wanted to put it you directed it to a directory you created on your "C:" drive, "C:\Foo". In Regedit use "find" to search for any references to "C:\foo" and after careful checking, delete those references. This btw can be very time consuming but is far more reliable than commercial registry cleaners, tho CCleaner is pretty good in capable hands.
Also incidentally, Malwarebytes is exceptionally good Malware detection and removal software IF you keep it updated at the very least, weekly. Your choice was excellent. I have never had even an optional positive deleted that caused problems but YMMV, so if and when in doubt, backup.
Finally please allow me to extend what someone briefly mentioned here and that is Live Operating Systems. These are self-contained bootable systems that commonly run from CDs, DVDs, and USB drives including thumb/pen drives. If you have an optical drive this is best because, once the burn is closed, they can no longer be written to, therefore all but "uninfectable", a guaranteed clean environment. They also commonly have access to the internet so anti virus/malware apps can get updates when the app is loaded into RAM. This is by far the preferred method of scanning, since an infected hard drive system, can have processes loaded very early on that facilitate a virus hiding itself. Safe Mode can ameliorate this problem but is not infallible. Scanning from the outside in is vastly superior.
My favorite Swiss Army Knife Live System by far is Hirens Boot CD, currently at v15.2. It has an amazing amount of high quality tools, and although it used to contain some "greyware", now has Freeware legal around the globe. The list is so long it is prohibitive to show here so below I will include a link to the list as well as a YouTube video on the wheres, whys, and hows.
One important tool is Clonezilla which can take a snapshot of any drive or partition and create an image file that can be restored in the same place or elsewhere with exactly the same parameters (including boot code) or expanded, say to migrate a system to a larger drive/partition.
The included partitioning tools will reveal any hidden partition which will solve your question of an install disk. The scan and clean tools will hopefully get your existing system back to a workable state.
OK so here is the overview -
http://www.hirensbootcd.org/hbcd-v152/
Tutorial (1 part) -
For a more thorough tutorial (5 parts) -
Be sure to look at enough video to see how to employ the boot menu. There are DOS-based programs, a bootable XP desktop (PE) as well as an extremely handy and powerful Linux system. The boot menu also includes it's own bootloaders to boot any bootable partition on your hard drive or external drives. It is an immensely powerful and versatile tool but like any sharp tool you can "cut yourself" so be careful and deliberate. You will be well rewarded, I assure you.
