Q: MACBOOK AIR SLOWER THAN A SNAIL

few months back my Macbook Air had a battery issue. Yep another swollen battery.

So I order a new one. I install said new battery yesterday and start her up.

After 5 minutes or so I get to the login screen.

another 5 or so minutes and it logs on.

I go to move the pointer and its shooting all over the page like a maniac.

Very disjointed and extremely slow to respond.

I Try PRAM reset.

I try all the other stuff that is in all the forums.

I click on the apple logo and wait another 3 minutes for the menu to drop down.

I click on "about this mac" and check hard drive space. Says I have 84gig remaining of 250.

I call help centre and they try system management reset . Try to get to disc boot mode and format hard drive but it stalls 4 times and won't load it.

Go back into my profile and go to disc utility. Repair hard drive.......... All of a sudden i'm showing only 2mb of hard drive left.

WHAT THE F**K?????

Try to empty bin...It stalls with 5 files left to clear.

Try to transfer info i want IE pics and music files over to external hard drive. No it won't identify or acknowledge the external hard drive.

ARGHHHHHHHHHHHHHHHH

Any ideas?

I can't even format the **** thing as I can't get to disc boot area to erase it.

Now because of how long it took me to get the battery, I am still on the last version of Yosemite.

Can anyone help me with this?

Cheer sin advance...

David