Slow performance spinning wheel

I have had lots of performance issues with this macbook. Rebooting takes well over a min to open all the programs.

So Far I have:

- Updated Microsoft Office to latest version (made the issue worse)

- Reformatted Harddrive and installed program/reloaded personal files(did not use time machine)

I have a early 2009 macbook pro 15" that runs faster than this laptop.

The CPU does not seem overworked.

Suggestions?

Upgrade RAM to 8 gig?

Replace Hard drive?

Do not want to sink to much money into it. I plan to replace this unit in a year but need to use it for work until then.