It's possible that the network adapter in your laptop is inferior to the ones in your PS3/TV and can't connect/hold the connection. I would guess for one of two reasons:
- The adapter is just old and has a weak signal
- The adapter only supports 802.11b/g networking and the network you're
trying to access is 802.11n and doesn't have backwards compatibility
(I've had similar problems with this one in the past)
In the first case, you should try accessing the internet in different areas of the building to see if you can get a signal anywhere. If you can and the signal just isn't strong enough for your laptop in your apartment, I'd recommend getting a new USB wifi adapter. I got a TP-LINK TL-WN822N a few months ago myself. It's fairly inexpensive, high powered, supports 802.11n and improved my signal a lot. This would also probably fix issue #2, but might not be necessary, because...
If you can't get a signal anywhere in your building, my next guess would be a network compatibility issue, most likely the one I mentioned. You can check whether your card supports 802.11n with the method in another answer. If it doesn't, see if you can check with whoever manages the network in your building to see if the network is 802.11n only and perhaps politely ask them to implement backwards compatibility (this is generally pretty simple).
EDIT: I'm leaning toward the second option. If you're running XP your laptop is probably pretty old and likely wouldn't support 802.11n. Incidentally, you may want to look into an operating system or perhaps even computer upgrade as XP will be losing support in less than a year.
It could well be something else as well, those are just my first two guesses. The usual stuff about upgrading your network drivers and whatnot applies as well.