Help!!! my laptop freezes all the time. ):?

So I have a Dell inspiron 1525, I've had it for 3yrs and recently its been acting up and freezing all the time. I use word and excel a lot and the programs take forever to open up. The internet also takes a while to open up or it says "not responding". I've noticed that after like 30min of being on the bottom of the laptop gets very hot. I have spyware doctor and McAfee security installed on my laptop. I used my laptop a lot for school so its very frustrating that it doesn't work. I'm not the most tech savvy person so idk what to do to make it work better. Any suggestions and what to do? Should I take my laptop to like best buy and have the geek squad take a look at it?? Any help is appreciated thanks.