David Johansen
not "runs a program", IS an executable file. IS a program.
a computer is a box of hardware that runs software programs. malware is malicious software code, and just like scott, the good stuff is available without charge. http://www.malwarebytes.org/
wont interfeer with your antivirous program. neither will housecall.trendmicro.com a decent free scanning tool.
if you want, hijackthis, before norton got a hold of it, that i can send you. a really powerful program that allows you to rip things out otherwise difficult to delete.
as for the email attachment, as long as you dont/didn't save and click it, if its just on a drive you can just delete it. Shift +Delete skips the recycle bin.
note windows 7 and 8 are spying on you behind your back, you accepted it in the license agreement.