I have tried many times to uninstall mcfee package from my pc but it just failes every time this has lead to errors on my pc on start up and when i go on the internet

Is it a package you've bought? I only ask because i downloaded it from AOL as a subscription and had similar problems. I had to unsubscribe from it first before i could get rid properly.

I now run AVG...

I had the same problem with Norton, eventually I found a full uninstall tool on Norton's web site.
Check McAfee's site, or ask them.
Best of luck

Download and run this McAfee Uninstaller.