Q: My MacAir keeps picking up adverts etc - i deleted previous internet links which helped - is there a cleaning system i can set up on my Mac Air to stop this happening again

Fixes for Adware and Pop-ups:

1. Malwarebytes
2. DetectX 2.11
3. Remove adware that displays pop-up ads and graphics on your Mac
4. Stop pop-up ads and adware in Safari - Apple Support

I have had good results using GlimmerBlocker.

Fallen Angels wrote:

 

My MacAir keeps picking up adverts etc - i deleted previous internet links which helped - is there a cleaning system i can set up on my Mac Air to stop this happening again

Just to expand on what theratter said, never, never, NEVER put a "cleaning" system on your computer.  That includes any of the following programs:

• AVG Cleaner
• CCleaner
• CleanMyDrive
• CleanMyMac
• MacCleaner
• MacKeeper
• Memory Cleaner
• TuneMyMac

These programs are bad, bad news, and negatively impact the performance of your computer.  Stay far, far away from them.