Home page changing

My Sony Vaio has just been repaired by Sony and now after installing IE 11 and Chrome and Firefox my homepage has changed to http://istart.websearches.com (see attachment) and chrome is not accessible. When I put in a webpage I want I get the message that Internet Explorer is not working. Also about 6 other programs appeared as having been installed in the Control Panel and I have managed to delete those, but this one cannot be uninstalled.

How do I remove this please.

Tilly

 

thanks mate for your quick reply.

 

Unfortunately no. The computer has gone back to Sony as there were hardware problems, I think the motherboard may be cracked. But again, thanks for your suggestions. I will bear them in mind for future reference.
Cheers
Tilly