Adwords low quality score, landing page 1/10 help?!

Hi there.
Today all keywords across 3 of my websites changed to a status of “Rarely shown due to low quality score”. The landing page score for all keywords is now 1/10. I’m hoping someone can help me find out why, and maybe advise me if there’s anything I can do about it, or whether I should just give up?? I’m rather stressed by this, as this is 6 months+ of solid work.

The three sites I run are slr-lens.co.uk, camera-buyer.com and tech-saver.co.uk. They are sites which combine information & reviews for cameras & computer gear, and links to buy the items on ebay and amazon. Ads have been running fine for 3 months, however today everything has stopped. I am aware google doesnt like affiliate sites, but I was hoping the combination of quality content and affiliate links would be o.k. Am I wrong, should I give up??

The text content on a lot of my pages does come from wikipedia, would that likely be a cause for getting all the sites hit with a low quality landing page score because of duplicate content?

I also have a large adwords account, holding 45,000 keywords across a product range of around 400 items. Therefore a large percentage of keywords generate 0 or nearly 0 impressions. Would that also have an impact on a low quality score landing page?

In a typical ad I would put a specific price for an item (e.g. a Canon 5D camera) which would be a ball-park figure, but not necessarily exactly the same price on the site itself, as there will be many canon cameras listed on my site each with differing values. Would that also likely cause the low quality score on the landing page?

If anyone could please offer me some suggestions or advice, I would be most grateful. Is there anything I can do, or am i fighting a losing battle??

A very stressed Google Adwords user.

Take this as a lesson learned. Always diversify your advertising. Don’t put all of your eggs in one basket.

Use MSN adCenter, Yahoo, 7Search, the list goes on and on.

Google brings the most traffic, but not always the best conversions so it is a good idea to look elsewhere while this issue is being worked out.