I am learning this whole SEO thing now few questions on page redirects.
To explain I went into my webmaster tools and noticed a few thousand pages not being crawled because of errors and noticed they are pages I deleted a long time ago.
BASed on that
1. Does this affect you whole site SERPs if you have crawl errors?
2. How do I enter pages I want google to stop looking for?
3. I want to delete products and create them again with a better product ID. Will page redirect work if I delete products and create them with the new ID pointing the old id to this new id?