My computer got slammed with adware/spyware, stating I have critical errors. I have Ad-aware se,everytime it runs it finds 300 critical objects. I tried downloading free error guard, but when I run it the program tells me it has too many errors and I have to register and pay

I am getting pop-ups evrything else you can imagine. The pc is new and has been running fine until yesterday. I use Microsoft int. exp. Any suggestions Thanks