COMPUTER help!!...?

First of all, i tried to open the internet, and it said that it didnt have enough memory press ok to terminate the application. I tried to open spybot search and destroy, it said the same thing, then i switched user, but then it said the computer has been locked ''Username - HP_Owner then password - Enter or something, but i didnt have a password, then it said incorrect, then it said not enough memory, press ok to terminate the application again, so i switched the computer off, turned it back on and its ok at the moment, the internet came back on, but it's going to do it again because it did it before while i left logged on, what is wrong with my computer? it was working fine before. I have spybot search and destroy, yahoo anti-spy, and avast! anti-virus, i checked for viruses on tuesday and it didnt have any, and i removed some spyware aswel with spybot. but it keeps saying terminate application etc, Can someone help me sort this please?

Thanks

COMPUTER help!!...?free anti virus

can you give us your specs on the puter. how much memory do you have right now and have you loaded your puter up with endless files. try doing a disk clean up and defrag if you have not already. you may need to upgrade your memory. also try windows cleaner advanced (i heard it works real well)

COMPUTER help!!...?internet security software

maybe you have a error, sometimes spyware embedds itself into real registery keys and your anti virus removes the keys try a system restore.
fist see if you can rebot the system then they should all go away
Did you try to reboot in safe mode? normally pressing f8 while booting up (bios windows) once login go to control panel and disable any account that you are not using like quest account and so forth. Try cleaning the pc while in safe mode and then reboot.

Its a good idea to list your pc specs it would be very helpful to whoever wanted to help you.