Startsear.ch \ Search.searchcompletion.com do not make much harm. Probably, these sites merely rarely insert pages in which persons standing behind these pages are inserted into blended selection websites derived from searched of renowned providers such as Google.
However, due to becoming of the above sites a start page and default preference of web-browser search facility in some uncertain and unclear fashion, users are seeking removal of Startsear.ch and search.searchcompletion.com in the sense of changing settings of web-browsers.
This requires users to perform steps specific to particular browser. Click here to order free scan to ensure there is no hijacker infection behind  the two search providers in question.

Having the malware onboard puts your computer system safety and stability at risk. Even if the above sections of this review state that infection is unlikely to slow the computer down or do other damage, the programs it may come bundled with are very likely to do that. In this connection, be aware that the reviewed parasite is often bundled with so called subservient malware like virus or worm.
That is to say how important is at least to start removing Startsear.ch \ Search.searchcompletion.com automatically, for that would launch free malware scan and thus aware you about all the infections actually threatening your computer system.
In order to start free scan as a first step to the final goal of Startsear.ch \ Search.searchcompletion.com removal and other infections disposal, click here.

How do I get rid of Startsear.ch and search.searchcompletion.com in Internet Explorer?

Select Tools, click Manage Add-ons in the drop-down list. In the resulted table, go to Type, and  choose Search Providers. Your target is in the table to the right. Its name is Web Search. Get rid of Web Search clicking Remove button below.
Apart from altering search provider, you may need to reset home page. In Tools menu, select Internet Options, click General. In the box, if you see one of the above unwanted url names, delete it and type your own preference.

How do I remove Startsear.ch and search.searchcompletion.com in Mozilla Firefox?

Click the magnifier icon at the right upper corner of Mozilla window, select Manage Search Engine, and go ahead to removal of Web Search.
Home-page is to be altered, if necessary, through Tools menu, where you need to click Options. Select General, and set the page you like to start your browser by default with instead of the annoying search provider specified in the box.