Ok, then there is basically nothing stopping someone from using your machine. The Windows passwords are super easy to disable/get around. If you put a password on your hard drive, this is MUCH more secure. Even if someone would put that HD in another machine, it would still require a password, otherwise it cannot be used. It can't be seen, formatted, etc. It will just fail to work. The only way to access the data is to remove the drive platters and put them in a new HD assembly...which would be impossible without the use of a clean room.
But I digress....the point is:
So, basically this is good for you, because hopefully as soon as the person boots the machine near somewhere with Wifi access, it will transmit its position to the lojack company. My advice to you would be to report it stolen with the police AND Lojack ASAP. File a police report, get a case number and go here:
http://www.lojackforlaptops.com/repo...or-laptops.asp
This of course assumes that you properly registered your machine with them.
When you visit that web site, your machine will be flagged in their database. Now, your machine contacts their server once a day or so. Next time it contacts their server, the server will see that it was flagged as stolen. Now, the laptop's "polling interval" will be set to every 15 minutes.
Even if the person is using "free" internet like at a coffee shop or something, they can still be traced. LoJack will send its IP address to the police, and the police will contact the ISP that owns that IP so they can find out where exactly it connects to. If its somewhere like a coffee shop, the Police can very easily send an officer with a description of your laptop (and possibly you) and search the area for someone with a machine that matches the description. They can then very easily look at the bottom of the machine and see the service tag. Even if it has been removed, the tag is still accessible in the BIOS. If you're not sure what your tag is, find your Dell invoice or call them and ask. If you provide enough information, I'm sure they can recall it for you.
Depending on where you live, the police might just ignore your report because they have "more important things to do". DONT LET THIS HAPPEN. I know it sounds weird, but sometimes the police just take your report as a record that something happened, with no follow up. The chances of you getting your machine back are very high IF they cooperate.
Good luck and let us know how it turns out!