what are some ways to check if there is anything wrong with some of my hardware?

[Inspector Jihad]

my computer is really acting up.

 

[Bateluer]

There are a few programs such as Memtest86, which can test different aspects of your hardware.

What we'd need are some specifics about your problems and your system specs, in order to help you diagnose the cause.

 

[BigPoppa]

I work for the Geek Squad, and we use a couple different programs for hardware diagnostics.

PC Check - scans over basically everything.
Memtest - obvious. Let it run through quite a few passes to ensure your memory is good. Only running 1 or 2 passes can lead to not catching errors that will eventually propagate.
DFT - Tests your hard drive. I'd recommend backing everything up before running this (and any diagnostic, really). DFT can brick a HDD that is already going south. Its fine on a healhty HDD.

Also, QA+32, but I don't really like it.