Updating Firmware Ruined My MacBook

I recently updated the firmware on my 2007 White MacBook Mac OS X Version 10.4.11 which is still running on tiger to "MacBook EFI Firmware Update" (1.1) which made my laptop: 1) run slower and 2) I cannot open flash required videos (youtube for ex) anymore

When i try to access any type of video it tells me to download the new version of flash player, the flash website tells me that my system requirements are not met to download flash (when before the firmware update, my system requirements were up to par)

So with that said I have two questions:
Is there anything I can do to simply fix this?
Should I bring in my laptop to an apple store or should I bring it to a different computer repair service?

How did you update the firmware?

I don't see that as a Firmware issue. It's probably a Tiger issue. New Flash version are no longer made for Tiger and older ones are being locked out for security reasons.

The firmware update you applied has nothing to do with Flash. The reason Flash isn't working is likely what dtravis7 stated.

Here's what Apple says about that firmware update:

This update improves the performance and reliability of Intel Core 2 Duo processors and fixes issues with Boot Camp for MacBook computers.

After the firmware is successfully applied to your computer, your BootROM Version will be:
MB21.00A5.B07

You can confirm the version of the BootROM installed on your computer using System Profiler.

Make sure the firmware update was successful by following the Apple instructions above.

Running a machine with an unsupported OS can be dangerous, and as you've noticed, rather inconvenient when a vendor third party vendor (like Adobe) abandons their own support for it. For a machine of that vintage, I would recommend upgrading to 10.6 at a minimum. Fortunately, even though it's two major revisions behind, it's still sold and well-supported.

Mac OS X 10.6 Snow Leopard - Apple Store (U.S.)

....and if you're going to do it, do it soon.... because eventually Apple will stop selling it and at that point, the prices for any retail copies will skyrocket.