I'm not sure if you've run into this when you're developing custom webparts or adding 3rd party webparts to a page but this happens to me quite often, I get an error stating that the page cannot be displayed and I right of way I know it's a web part I added to the page that's causing the issue but I can't get to the page to delete the web part. I don't want to open SharePoint designer either, so how do you delete the web part with the browser if you can't accesss the page?

Use the following URL on any SharePoint site to see the webparts you have installed on your SharePoint page

/_layouts/spcontnt.aspx?&url=[your_page_url_goes_here] 

So if  the page you're having issues with looks like the following

http://www.yourserver.com/site1/default.aspx

To see the web parts on that page you would use the following link

http://www.yourserver.com/_layouts/spcontnt.aspx?&url=/site/default.aspx

When you get to that page you'll see that you can Close, Reset or Delete web parts on the page that you specified.

Hope this helps!