Problems with Safari and Firefox (HTTP?)

Question

Problems with Safari and Firefox (HTTP?)
On a laptop G4, 10.5.8 and Safari 5.02 I experience the following:
On the account of my oldest daughter everything works fine, i.e. wireless internet works and no problems with mail or safari.
On the same laptop, on the account of my other daughter, the wireless is OK, she can mail etc. But safari nor firefox works. It says: can’t find server (whatever site) and in the activity window it looks if safari tries to open files (in the safari preferences-folder) in stead of http. Same applies to Firefox, so maybe it has more to do with HTTP in general?
What goes wrong? What to do? I tried the following on the host terminal (tips from Apple)
defaults write com.apple.safari WebKitDNSPrefetchingEnabled -boolean false
and
defaults delete com.apple.safari WebKitDNSPrefetchingEnabled
but that did not help,
Nanne

Answer 1

I'm still wondering why it happens now at this moment in time...
PC does seem to be a bit odd & inconsistent, the few times I've tested with it, at least so far as we content filtering goes; and if I remember rightly, you're not the first to report previously ok settings suddenly preventing some or all internet until pc is switched off altogether.
It may work when re-enabled