As the other guys have said,, you're barely using your computer to it's capacity even if it's 5-6 years old.

Find a good computer geek in your area. Place to start is call around to the business's in your area, ask them who they take there computer problems to.

It really is simple to reformat the hard drive, IF,, IF you have the original disks that (hopefully) came with the computer.  I've redone a few for friends who's computer's were 'old and slow" as you're describing. 

Wiped the Hard drive, reinstalled with boot disk, and reloaded programs,, works like brand new.

It should take about 1 hour give or take to reformat the hard drive. Around "here" the geeks charge $60/hour.  Lot less than buying a new computer just to surf the net and yack on here.