Computer running very slow?

I am new here. I do not know if this is the right place to post this. My computer just started running very slow. It takes my yahoo e-mail a very long time to load and pages a long time to load. I have no idea what is going on. Using AVG Anti-Virus Free version. It had not detected any viruses. Can it be a spyware issue? Everything was fine yesterday. What can I do to fix this?

 

To start work through this thread http://forums.majorgeeks.com/showthread.php?t=106650

and then work through this one for StartUp Processes http://forums.majorgeeks.com/showthread.php?t=149804

Post back after you are done and tell us how things are going.

 

Thanks for the help. I'll let you know how things work out