BleepingComputer.com: smss32.exe problem

I apologize ahead of time for the limited information I will be able to provide, but I am very much a novice when it comes to computer viruses. For a couple days my computer has been running slower than normal, and I had been flooded with "nExplore" pop-ups every time I went on the internet. This morning I noticed my desktop background was changed to a blue screen, and there was a new icon in my system tray (I believe that is what it's called). A dialog balloon kept popping up about my computer being infected. I ignored this and began to research what the problem might be but with little success. I downloaded MalwareBytes Anti-Malware, but when I went to run the program, I received an error message saying the mbam.exe file was missing. At that point I couldn't do anything more.

I came home from work this afternoon, and now I can't open Task Manager, System Restore, Command Prompt (or any other program for that matter). I also cannot access the internet from that computer anymore, so downloading cleaning software is out of the question.

I tried starting the computer in Safe Mode to see if I could access any of the programs (or the internet) that way, but it was more of the same.

Please advise me on what I can do to begin to resolve this issue.

Thank you.