You didn\'t specify what browser you\'re using nor what operating system you\'re using. Assume you\'re using Microsoft Internet Explorer (IE) and Windows 7.
When I see the "Ask" homepage and/or "Ask Toolbar" problem, it usually tells me there\'s adware/spyware on the system. Ask components are not just a single program but usually consist of multiple pieces that you have to take care of. You may need to take aggressive action to remove "Ask" features. It can take quite a while to remove Ask and return control of the home page to you. This article from PC Magazine will give you a decent start: http://www.pcmag.com/article2/0,2817,2421591,00.asp
There are a thousand web articles out there talking about how to remove Ask components, both automated and manual. Some of them start out with a treatment of the system using MalwareBytes or SuperAntiSpyWare programs. Both of these offer free scanning and cleaning. They will not remove Ask but will help you get rid of most other infestations to ensure a stable platform before you begin. I often find the manual Ask removal procedure to be the most thorough but one that takes more time and effort. Try the easy ones first - you may get lucky.
Once you\'ve ridded your system of the Ask junk, you will then be able to have your Google Home Page back. In the IE browser, call up Google.com. Then use Tools > Internet Options. Look at the top panel of the General tab. Delete everything in the field. You\'ll see a button to the left called "Use Current", click that and Google.com should now be your home page.
If you fail to completely remove Ask, Ask SearchBar, Ask Toolbar, and all Ask components, I\'m afraid this Ask home page hijack may come back to haunt you until you do get rid of it.
Ask is usually injected on a system when you download and install software, for instance Java. Most reputable software vendors (like the folks who make Java) will let you OPT OUT of the Ask component -but- it is up to you, the user, to pay attention and take the OptOut path. Blindly clicking through a software install, whether downloaded from the \'net or off a disk, is just asking for it.