Unless you are compiling your own Chromium browser, it's quite unlikely that someone has busted the source code for your browser.
Start in Safe Mode Most web browsers have a safe mode which starts your browser with addons disabled. This will allow you to see if your issue is being caused by an addon and will allow you to disable them all. You can then start enabling your addons one at a time until you see the issue and can pinpoint the offender
Is all your software up to date? Ensure that Windows, your AntiVitus, AntiSpyware, browser and addons are all the latest version. A lot of exploits target out of date software and exploit bugs which are fixed in newer versions of applications.
Reset your Browser. Most modern browsers including Chrome have the functionality to reset the browser and your profile within it... this will kill off any addons that could be responsible for the issues you are seeing
Reinstall your Browser This is just one step further along the same route - a reinstall will hopefully mop up any infected DLLs etc that could be forming your problem
Full Scans Install a good AV, update it to the latest definitions and scan your machine fully. It may also be worth sourcing a few free AVs, installing - updating - scanning - uninstalling as no single AV can catch everything (and haivng multiple installed can cause real headaches). This also goes for anti-malware and anti spyware solutions.
if none of the above fixes it - try windows in safe mode to rule out another exe running on your PC and injecting the code.. then you can use MSCONFIG to start disabling processes and services that could be responsible. CCleaner is also useful for this.
Hopefully some of this advice will help you figure it out - but I very much doubt chrome itself has been hacked.