Google PageRank disappeared

The PageRank for one of my websites completely disappeared about a week aogo. The main pages (4) used to be PR4 most of the inner pages PR3 (20) and PR2 (10).
All of a sudden they all don't show any PageRank in any of the tools I use.
The pages are not dropped from the index and the site still has 10 top ten rankings in Google (according to Webmaster tools and manual testing).
It's all white hat SEO techniques anyway so there would be no reason to drop the site.
I gently modified the pages recently (Title Tags, Description Tags, ALT Tags and internal links). These measures trippled the top ten appearances throughout all search engines so it should not have a negative affect on PR.
And all inbound links are still there.

Does anybody have an explanation

 

what is url?
check digpagerank

PR is returned ZERO you might be hitting invalid ip.

 

Thanks. - What's digpagerank?

 

1)
Try this tool to check your PR in different DCs
http://www.seochat.com/?go=1&option...ageverify=7NPYC&timehsh=rLTFx6o=&submit=Check

2) try to check PR for various variants of typing your site url
like

site.com
www.site.com
www.site.com/

etc

 

I just used http://www.digpagerank.com and according to that program the site is still recognized as PR4 by twelve (12) of 57 datacenters.
That seems like a low number. Does someone have the latest number of datacenters?

 

digpagerank has over 700 ip list
calm down and check again.

 

how old is your site?

 

I had this very same thing happen to me. I had a PR4 or 5 and now its zero.
http://www.fullscreen360.com. Just checked Future PageRank Tool and it says the same. The only thing that recently has happened is a couple of links from stumbleupon and a big volcano website. The spike has pushed my bandwidth from 100 to 700megs per day. Think that tripped G?

 

I have alot of traffic from Google, on top of 1 SERP with image of Map beside the result, but the PR only 0 (grey bar)