I've troubles with Perl

I don't know why, but it simply stoped to work

I've uninstalled and reinstalled it, but nothing occurs!
I've tried the version 5.8.0, but nothing!
When i digit the comand line it simply doesn't work like before, if something occurs it tells me that the "format is unknown" What's happening

I tried also the restore utility of winXP, but nothing!!!!
HELP