Can't get on the internet!

I have an Acer AspireOne laptop with Windows XP.

My computer starts normally but I immediately get the following error message:

Windows cannot find 'C:\DOCUME~1\TIFFANY\LOCALS~1\Temp\csrss.exe'. Make sure you typed the name correctly, and then try again. To search for a file, click the Start button and then click Search.

When I click OK I get this error message:

Could not load 'C:\DOCUME~1\TIFFANY\LOCALS~1\Temp\csrss.exe' specified in the registry. Make sure the file exists on your computer or remove the reference to it in the registry.

When I click OK again everything works normally except for when I try to get on the internet. When I click on Internet Explorer I get the message 'Internet Explorer cannot display the webpage'. I'm successfully connected to the internet but I get this message regardless of the web address I tey to access.

I'm afraid that I've somehow deleted something important and I'm not sure what to do.

Please help!

Thanks,

Tiffany