v201 Problem Setting Up Attributes

I just started a new shopping cart yesterday, and installed version 2.01 from scratch. Things were going pretty well until I started working with attributes. Per advice received on another post, I started off by studying https://docs.zen-cart.com/user/products/attributes/. I set up two options under Option Name Manager (half-pound and one pound), and selected Dropdown for each one.

Then I went to Option Values and set up the names and order numbers for each one. So far, so good.

Finally I went to Attributes Controller and assigned prices (choosing the --none option under Price) and weights to each of the options I'd set up. Again, so far so good.

Then things started to go wrong. Suddenly I couldn't access any pages in the admin section. The pages kept refreshing again and again so fast, nothing would appear. Finally, after much experimenting, I discovered that SOMETIMES I can get the page to load properly if I manually type www. in front of the url. Often it doesn't work, and the page refreshes a million times at rapid speed. But once in a while, it accepts the www. and displays the page. (It does the same thing on Firefox and Chrome, btw, so it's not a problem with the browsers.)

In order to actually make any changes, I have to clear my cache and login AGAIN. Sometimes I have to do this after every single page I review, and sometimes it will generously allow me to access 2 or 3 pages before it starts screwing up again.

Could someone please help me fix this? Because it's driving me crazy. (And it's a really short trip!) I should not have to clear my cache every three pages just to make edits and additions to this shopping cart!

I don't know what caused it; I only know it started after I created my attributes. Yesterday and last night, it was working just fine.

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Sidenote: How can I get rid of the lines "Starting At" and "Please Choose" on the listing pages? They're not necessary, and look really stupid sitting there for no reason.

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http://candyland-sweets.com/index.ph...products_id=10

Many sincere thanks to anyone who can help me get this fixed!!