For some reason, I can't access the internet. Either through my wireless or my Tmobile dongle.
It says..'Problem Event Name APPCRASH'

Can anyone shed any light or help to fix the problem?

Appcrash is a generic term. The error message should state which application is crashing, then you can plug into Google, "appcrash" and appname, such as "iexplorer.exe" for clues.

Do make sure your system if free of malware by running full scans with your updated anti-malware solution.