i have a 4yr. old hp compaq pressario laptop xp. it worked great til 3mos. ago, when all of a sudden a small silver tab would appear and it says alert, the url is not valid and cannot be loaded, it has a clickable ok, when i click that most times it disappears and other times it just stays and doesn't let me do anything and makes it almost impossible to shut down, a few times i had to shut the power button. i have used ccleaner and i think it's called hijack a malware thing, i don't know what that really is but i did it, then i went to my programs and removed all the games that came with the pc and anything that said i rarely use. i also have norton and they scan everyday. i'm ready to toss it in the trash. i'm hoping someone can help me and i can keep this laptop, it worked great til this happened, and i have no idea why it happens. it's working perfect now, this afternoon i had to shut down twice to get it to work.
thx. in advance for any help.

thx. ellie