I totally agree, daffy. I can't believe the number of times I see this being given out as sensible "advice" [sic]. System restore really should be viewed as almost the last resort, and one step up from a complete rebuild.
The OP doesn't say whether she (thinks she) has a fixed IP address or not, but I'm betting she doesn't. Domestic IP addresses get changed all the time, and not all ISPs offer fixes ones to the domestic channel. Some offer what they call "static" IP addresses, but they are just a con as they can (and do) change e.g. if you change your router.
Presumably, the OP needs the same IP address either because she is hosting something or because access to a remote service depends on it. In that case, she should investigate something like DynamicDNS.