my system is running slow

Definitely not a Classic operating system. Those haven't been around since 2005.

If it is a brand new Mac bought this year, it is running Yosemite. Go to Apple menu -> About This Mac to find out the Mac OS X version. Then use this tip to find where to post:

http://discussions.apple.com/docs/DOC-2463

Get Etrecheck to copy/paste the contents of your system, as that will help others isolate what the problem is. And backup your data, as some issues require doing diagnostic that could expose a dying hard drive, or could not. Without any data to go on, we can't say for certain.

Try these steps:

- Shut down your Mac

- Wait until your computer turns off and after that press the Power button

- Right after you hear the startup tone, press and hold the Shift key

- Release the Shift key when you see a grey Apple sign and the progress bar below this sign

- Once you see Desktop, start a Disk Utility scan to detect and repair file system errors (don't forget to choose your main hard drive)

- Click on Verify Disk and then, if asked to fix problems, on Repair Disk

- After this, click on Verify Disk Permissions and then on Repair Disk Permissions

- After the process is finished, shut down your Mac and turn it back on after about 30 seconds

Apart from that, take a look at this Apple article and follow the instructions on Resetting NVRAM shown there:How to Reset NVRAM on your Mac - Apple Support

Try resetting the System Management Controller: https://support.apple.com/en-us/HT201295

To help you narrow down the cause what makes you think your MacBook is running slow? Is this when booting up, when logging in? When launching a specific application, when transferring files or when surfing the internet?