Do I need to use a broadband provider's router?

[Chris cc]

The old one is doing OK. The lump hammer remedy for problems with it was never carried out. I've changed provider and the old router is still as it was.

[Andy]

You don't have to use the broadband providers router (they tend to be cheap and nasty anyway) but some routers are set to only run on one provider (*such as the BT homehub).
All you generally need are the settings - copy them all down or take screenshots, otherwise you may need to contact your provider who should be happy to supply them.
If you put a new router in there, the worst that can happen is that you cannot configure it and you can always put the original back (just don't ever change the configuration on the original)

[raina_vissora]

Router or modem? I've never had an ISP provide me with a router. I've always bought my own routers. The most I ever have to do to get them working is power cycle the modem after I've hooked it up.

You usually don't need to use a modem provided by your ISP, either. Though most ISPs have a list of models they "support" (meaning they will offer you limited tech support if you can't get it working on your own). Usually, you will have to call your ISP once your new router is hooked up and have them "activate" it (which basically just means they whitelist it's MAC address).