Will removing robots.txt make the website 'searchable' again.
Curious if you had a robots.txt to avoid indexing, but changed your mind and wanted to get indexed.
The Robots.txt serves as a guide for search engines when they arrive at your site and begin their crawl. If you are suggesting that you've disallowed search engines from crawling your site and decide you wanted it index thereafter, you may want to expedite the process.
Googlebot (Google's crawler), for instance, engages site depending on a number of factors, including "PageRank, links to a page, and crawling constraints such as the number of parameters in a URL", which are all based on a super secret computer algorithm.
One way to expedite the process of indexation is setting up a Webmaster Tools account (for both Google and Bing), and submitting your Robots.txt (which includes permission to crawl the site) and an XML sitemap. This suggests to search engines that your site exists and is operational.