Cannot connect to share by name, only by ip

Hi, i have acquired a laptop (xp home) and i have set up a shared folder on it, but the odd thing is i can only connect to the share if i give it a fixed ip on the lan, and enter the ip instead of the laptops name as the share address.
example
Do, map a network drive...and use...
\\192.168.10.50\Shared works fine, can read and write to the folder.
\\DELL\Shared tells me i should check spelling etc.

the laptop is named as DELL , and both the laptop and my Win7 are in the same WORKGROUP. Files sharing settings are enabled on Win7.

I'm under the impression that the previous owner of the laptop liked turning off lesser used services (its only got 256m of ram)
Is it possible a disabled service is causing this? if so, which one?
The only relevant one i can think of is 'server' for file and print sharing, but thats running.
Its not too much of a problem having to use a ip instead, but as is the nature of laptops, it gets plugged in in other places, and needs dhcp, and not a fixed ip on the lan.

Thanks for any advice with this.

P.s., i know its not technically a win7 question, but i thought i'd give it a try anyway :)

Let's try this - wild guess - do you have the online ID (windows live ID) component (for remote media streaming) installed? if you do, try uninstalling it... and see if this works.

Nope, its pretty bare, no live, just office 2007...

As chev65 was say in other thread you may need to run the network set up wizard on the XP machines if you want to see them from the Win 7 machines. Make sure all the sharing permissions are enabled on the XP machines also.