Problem with wininet.dll can't run applications.

Hi,

Spec:
Intel PIV 1.2G
1G RAM
200G ata HD
180G HD IDE
DVD r/w
Floppy 1.2
Windows XP Pro SP2
IE 6 / Firefox
kaspersky Internet 6.0

I am a newbie here and i need huge help please. A few days ago I found out I cannot run almost any applications, I received the following error message:
" The procedure entry pint InternetGetSecurityinfoByURLW" could not be located in the dynamic link library WININET.dll".

I search the web and apperantly this is common tu IE 7 instalations. The thing is that I dont use IE (I have it for my family) I use Firefox. I went to see if by any chance they install IE 7 and I still have IE6 version. But everytime I tried to run msn messenger and some other programs I received this error.

I tried to download this dll from the internet and copy it to system32 but I couldnt copy it, it just dont let me.

I have The BAT when i click on any web link in the mail that points to a link, I have the same error . In Incredimail I can't see my mails not even when I am making one because there is a grey window where I should see the mail and write the mail.

I really dont know what to do and I dont want to reinstall my pc..

Please! any help will be appreciated, thanks in advance!

Rose