Join Date: Sep 2009
Location: West Sussex
My Motorhome: Burstner Elegance
Thanked 277 Times in 260 Posts
Apparently it's a particularly unpleasant hijacker that will attempt to divert your browser, change your registry and do all sorts of unpleasant things, one of the less harmful being to slow down your browser. There are all sorts of solutions offered online, many of them wanting to charge and / or download things themselves.
If it's only recently manifested itself then, depending what operating system you are running, I would do a System Restore. Malwarebytes or similar should also be able to help as has been suggested.