No Connect with FF 2.0.0.5 and TB 2.0.0.5

Name:    Matze
Email:   infoatpc-scenedotnet
Product: Firefox
Summary: No Connect with FF 2.0.0.5 and TB 2.0.0.5

Comments: 
Hello, I have problems with Firefox 2.0.0.5 and Thunderbird. 

As soon as this version is not installed comes I any longer into Internet. 
No connection is indicated with both. 2.0.0.4 runs without problems up
to the update on 0.5 

Does someone know somewhat about an error?? MfG

Browser Details: Mozilla/5.0 (Windows; U; Windows NT 5.1; de; rv:1.8.1.3) Gecko/20070309 Firefox/2.0.0.3