I'm running a Gateway desktop and recently my computer began acting strangely. Any time I try to run a program or executable, it asks me to select with program to open that type of file with (as if it doesn't associate a program with the extension .exe). Also, only an extremely small number of programs are actively running on startup, with none of the programs I installed (Puresight PC, Malwarebyte's, and Skype being examples) starting up even though they used to. Anyways, I tried to use antivirus programs to scan and detect if there was malicious software, and there was, so I removed it. However, the software seems to remain after a restart.
Eventually I just decided I wanted to start over from scratch, so I found the boot disc I had previously used to reformat with and put it into my drive, then I changed the boot order so that my disc drives would boot first and made sure I was putting my boot disc into the primary disc drive.
This is where I have a problem. Instead of booting from my disc drive, it boots from my hard drive. I even disabled booting the hard drive altogether though the bios, at which point I received a "no bootable media found, please insert a boot disc and press any key." I thought I had finally figured it out, but even when the recovery disc is inside either drive, nothing happens. I simply receive the same message. When I boot to windows from my hard drive and tried to access the device manager through the control panel to see if I could reinstall the drivers, I receive an error that "rundll32.exe" could not be found, which I'm assuming is caused by the same thing that causes the "please select which program to open this type of file" error.
I'm scanning the computer right now with Malwarebyte's (I was able to open it by selecting Malwarebyte's as the program to open it with...), hoping that I can somehow get it to boot to where I can access the device manager, but I'm really at a loss for what to do since I can't install any programs (the "select which program to open" error prevents this).