
Yeah, here's a thought: try deleting it as someone pointed out, then reinstall the filter - but unblock PM or 'neuter' it a bit by ripping out its guts. Unless your dad is a sysop or whatever, he won't know the difference. Especially if you're the only kid using the PC (wouldn't work with an annoying sister telling on you)
If all else fails, give knoppix a try. You burn it to a single CD, and boot the PC with that CD. It'll set up everything you need: browser, video, sound, etc. and won't leave a trace when you reboot. Only caveat is, you can't write to HD IIRC.