Periodically, my Google Chrome home page (which I have originally set myself) changes spontaneously on opening the browser to display, instead, the page showing the rectangular small images of webpages I have visited before. In addition the bookmarks bar and my homepage icon has disappeared. I am also not directed to any other website location as might occur if a virus or malware were involved.
I can correct all of these changes back to my original settings the way I prefer (and nothing prevents my resetting it) and can continue to browse with no difficulty but this changed situation has happened several times in the past month. I had assumed that this was an idiosyncrasy of how Chrome (mis)behaves but worry whether virus or malware might be involved. I have monitoring by antiviral and antimalware software and run periodic complete scans and occasionally these find Trojans and other malware which are removed but this browser behavior seems to recur
I would like to prevent the surprises
As for your bookmarks bar, you may have closed it accidentally by the keyboard shortcut.
Hold Crtl+Shift+B to bring it back.
For the homepage problem make sure in options (under basics) that "Open the home page" is selected under the "On startup" section and that "Open this page" is selected under the "Home Page" section.
"Show Home Button" should also be checked under the "toolbar" section if your icon is not there.
If there settings keep getting lost then your config file might be corrupted. In that case you'll need to manually delete and reinstall all the chrome files
You probably installed a program, and in doing so an unnoticed option during the program installation was to change your home page (and/or often your default search engine). When installing new programs, uncheck any boxes that state they will make these changes.
You may be thinking of Safari which has that feature of showing the thumbnails by default, or Opera which lets you set up a grid of 9 (3x3) to 25 (5x5) thumbnails for the alternative to the default home page.
To check for SpyWare (MalWare), I suggest using these tools:
SpyBot - Search & Destroy
I want to display more Most Visited pages in google chrome, currently only 9 pages are being displayed, how can I increase them to 12 or 20 ??
The Dev Channel build of Chrome does offer a more customisable New Tab Page but this doesn't allow you to change the number of thumbnails.
So I don't think you can change the number of pages you see.
In case someone is still looking for this functionality, you can use Speed Dial extension for Chrome. However, I have not yet found a way to use the most visited websites automatically.
There may be a way to do this by writing an extension (I have not seen any yet though).
There's a topSites API that gives access to the Titles and URLs of the "Most Visited" pages (I think currently only 20 are tracked).
The thumbnails may be available via chrome://thumb/URL. I'm not sure if you can actually access the thumbs from extensions though.