Urgent computer help!?

recently (since 3 days ago or 4) i was on the internet and all was ok so idecided to shut it off to go to sleep.

on the next day i turned it on and it worked ok but when i went to the internet it was all different and i could do much things like i used to.

whenever i click on the big red "Y!" symbol or anithing else like homepage or any link under "favorites" a box with no name appears and says

"the file does not have a program assosiated with it for performing this action. Create an assosiation in the Folder Options control panel"

it has no name on the top such as "error" or something.Also everynow and then like 3o Internet Explorer webpages open up for no reason at all.I have done then virus scan and all using People Pc Internet Security Pack but nothing came up.So what do you think is wrong with it and how can i fix it?

PS the last thing i remember doing was going to Yahoo and downloading "internet explorer 7"

Urgent computer help!?hijackthis

Did you install internet explorer?

As this maybe file corruption, you could try reinstalling internet explorer but first:

This could also be spyware, remember spyware and a virus is two different things you will need a spyware remover too.

e.g. spybot search and destory

Scan anti virus, scan spayware remover and still nothing then reinstall internet explorer and try again.

If all else fails try doing a system restore, but that is another question lol.

Hope that helped