How about filling in your PC-specs under 'User Profile', top left on any page?
Good free firewalls are available from Agnitum Outpost, Kerio, Sygate and Zonelabs (in MY order of preference).
Paid for Firewalls: Agnitum Outpost is very hard to beat.
Changing a harddrive will only have an effect if it is a faster drive than what you have right now. Bigger is not necessarily better. Try to keep at least 15% free space at all times. Regular chkdsk and defrag also help, as does emptying the Temp directories, temp. Internet Files cache from whatever browser, uninstall what you don't use and/or need.
What do you mean by resetting your computer, pressing the reset button does nothing, other than perhaps get you out of a BSOD.