If your sole purpose it to get back into your machine, boot it to one of the Linux password removal / recovery CD's.  I understand 'learning something new,' but I usually setup my LAB to do that, not screw around on my desktop for which I 'forgot' the password conveniently, because I set one to keep prying eyes out.  Personally, I'd prefer to get back in, and be done with it.  If you're capable and understanding enough to password protect your machine, because you think someone's getting into it (not like it's difficult, but seriously...,) then these requests sound a bit too mundane for your experience, particularly if you're running around with a netbook and packet sniffers / CAIN.  Sounds m ore to me like you're working on accessing something that maybe you shouldn't be.

*** One note, a little research would tell you that Wireshark is a packet / LAN sniffer.  That's it.  It is NOT a cracking / hacking tool (isn't written to be one,) and cracks NOTHING by itself, except for decoding encrypted traffic (IF you have access to the encryption keys, and provide them.)  It's purpose in life is Network traffic analysis and troubleshooting, although it can be used in conjunction with other things to accomplish more. ***

So yes, I'm sorry, but I tend to side with Ketchup's gut instinct on this, and I'd agree that something sounds a little 'off.'  Is it me, or does this sound like someone wants to access a neighborhood (or other) computer, which just happens to be on wireless...?  Quite honestly, that's what my gut is telling me, as well.  I dunno, maybe it's just me.  (And I haven't had my sushi yet, today...)

There are myrriad of LM/NT password cracking toosl.
One of Them : Boot from 0phcrack Live CD and crack LM/NT hashed local admin passwords.
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GCIH, Security+

I did the same in a test lab a while ago so now I commit the unforgivable ... I write the lab passwords down but then I lock them in a filing cabinet.  Of course, I don't write down my "real live system" passwords!