I received an e-mail from Google and did these two steps:
"Follow each step below to ensure only you have access to this account.
Step 1: RUN A VIRUS SCAN ON YOUR COMPUTER
- Scan your machine for viruses and malware. Get rid of any programs found
during the scan.
- You may want to download Google Pack, which comes with free anti-virus
software:
http://pack.google.com/intl/en/pack_installer.html?utm_campaign=en&utm_source=en-et-hc&utm_medium=et&brand=GPMH&referer=ara
STEP 2: RESET YOUR PASSWORD
- Once you've run a virus scan, visit
https://www.google.com/accounts/recovery to reset your password.
- On this page, enter the username of the account you are recovering.
Google will send you a message at your recovery address with a link to
reset your password.
- IMPORTANT: Do not re-use your old password, or a password you use
frequently on other sites. To create a strong password follow these tips:
http://www.google.com/support/accounts/bin/answer.py?answer=32040."
