Your ISP probably gave you an email account as part of your access. Keep that account just for communicating with your ISP, and get a seperate account from a hosting company, or from a mail provider such as: mail.com hotmail.com, oryahoo.com
Never click on any links which offer to remove you from a list. All that does is confirm the email address works, and someone read the email.
Whenever possible, use a throw-away email address from one of the free providers.
Your bank/credit-union/whatever will NEVER ask you to "confirm your details" by email. If you receive an email like this, someone is trying to rip you off. You could try to pass it on to the authorities, but generally not much happens.
If you receive an offer which sounds to good to be true, it probably is. This is especially true of the "dead person, big money, no heir" scams. Check out scamorama.com for some amusing tales.
NEVER click on any attachments you didn't ask for. If the email appears comes from your favourite dear old auntie, the odds are that her PC has a virus which scanned her address book, and sent a copy to you without her knowledge.
Install one of the following scanners, and remember to keep the virus definition files current:
Wikipedia has a good definition of spyware
Avoiding spyware is much the same as avoiding viruses, but sometimes you may find some junk program you installed also installed some spyware as well.
Install one of the following scanners, and remember to keep the virus definition files current: