I have a US bought Dell Inspiron 6000. My power cord just went out on me and all my business specs are on this laptop. I have a presentation next week and not enough batt power to complete the presentation. Will a European Dell Inspiron power cord work on my laptop? My US power cord is 65w and the European one is 90w. The shop owner here is trying to tell me it will work without any problems but I want to make sure before I damage my machine. Thank you!

I think so.

I have an IBM thinkpad and the laptop itself takes a citcular plug (a little bigger than the sort you charge some mobile phones with) . This is attatched to the power cord/transformer box.

Im pretty sure that what happens is the box transforms the local power to a standard voltage for the circular plug

Therefore, if im correct you will just need the correct power cord/transformer box for your country.

Better check with an expert though

yes, the power supply is supposed to do the job of taking the existing power anywhere in the world and converting it to something the laptop needs.
At most there may be different ones for 110 and 240V, but most PSUs can handle both (and all you need is a different plug depending on country).

The different output power is a bit weird, but shouldn't pose a problem either if the machine is properly designed.
any properly designed laptop (or indeed any electrical device) will not draw more power than it needs even if more is available.
When in doubt, call Dell Europe's technical support (you'll find the numbers on the Dell website for the country you're in, or try Dell UK if that site is not available in English).