Help Required

[digits]

Over the weekend I have either been hacked or a nasty virus has attacked my machine.
Current Status: I have a new firewall and virus checker install. All working fine.
Problem: IE will open then close and pop up a box requesting to download my home page.
Outlook: i can download my emails but i get the follwoing error message on attempting to open the email "one or more parts of this message could not be displayed" I click ok then "There was an error opening this message There is not enough memory" I click ok.
I try to run the system restore the exe will not run
I try to run the help and support functions it will not run.
I can use MSN messenger ok.
I use Yahoo IM and it will all run apart from when sending and recieving message i can't see anything I type or what my contact types once sent.
I am unable to unstall software by using the control pannel normal options.
I have tried to install ie again and it tells me it has detected a newer version and closes.

I assume this is all symptoms of the same problem caused by either missing files or corruption of some files.

Would anyone care to help me !!!! Please!
I'm using xp sp2

[Thebranded]

if you are sure the virus is removed, i'd first make a backup of all important data, then try a win xp repair install, you may have to reinstall some application are it but should fix any missing files. If that also fails i'd do aa full install (format and install)