Although it's nice to surf anonymously, proxy services sometimes disable scripts by default. Many proxys have a "remove scripts" option enabled by default. You can try disabling that feature, or try using another proxy.
Sometimes there's nothing wrong on your end, but instead the website you're visiting has incorrect code. In this case, email the web administrator about the problem and hopefully they'll fix it.
For those not technically inclined, or for those who want to improve their computer performance overall, it is suggested that you download PC Health Advisor. It will scan your computer for any issues it has and fix the problems it has detected.