PC slows down and I see duplicate processes cmd.exe and calc.exe?

Sometimes my computer slows down to a halt almost like it crashes, when I open the task manager I see that i have more than 250 processes running, most of these are cmd.exe and calc.exe.

This happens a lot, even when I just watch a movie, browse the internet or something simple like that. I don't know why my computer slows down like this and makes all these duplicate processes. When all these duplicate processes start happening my CPU use is almost 100%, so I guess a lot is running through it's head, I just dont know why. My windows and internet explorer also crashes a lot.

I must also say that my computer is making a humming sound, so I guess one of the fans are dirty or something. Could this cause my computer to suddenly slow down like this and create all these duplicate processes?

I want to format and clean install my HD now, but just want to know if there is something I can do to save me from doing this.

P.S. I also want to know if it is possible to just format one partition of my harddrive (my system drive C, while keeping my data drive D: and all its contents intact?

Thanks a lot.

 

Thanks for the speedy reply. I checked my pc for malware etc, but I guess my checkers are not so up to date. I will post my logs. I guess its easiest and best to just format and reinstall my windows then. I just hope that I will get my internet up and running again so that I can start looking for all the programs and stuff again. Thanks again.

 

Im just going to reformat. Ive got a week more vacation to get my system up and running again. I think its about time for a fresh start. My system really is a bit of a mess now. I won't waste your guys' time with this mess. haha. Thanks anyway, you have been a great help.